CN113348688B - Method and user equipment for wireless communication of PLMN selection and cell (re) selection - Google Patents

Abstract

A method and User Equipment (UE) for wireless communication for PLMN selection and cell (re) selection are provided. The method comprises the following steps: system information of a plurality of cells is read by a UE on a first carrier frequency to obtain identification information of a plurality of public land mobile networks (Public Land Mobile Network, PLMNs). The first carrier frequency is an unlicensed carrier frequency. The method further comprises the steps of: reporting, by an Access Stratum (AS) entity of the UE, the identification information of the plurality of PLMNs to a non-access stratum (NAS) entity of the UE; selecting, by the NAS entity of the UE, one of the plurality of PLMNs as the selected PLMN; searching the plurality of cells on the first carrier frequency during a cell selection procedure; and selecting a suitable cell belonging to the selected PLMN from the plurality of cells on the first carrier frequency as a result of the cell selection procedure.

Description

Method and user equipment for wireless communication of PLMN selection and cell (re) selection

Cross Reference to Related Applications

The present application claims the benefits and priority of provisional U.S. patent application Ser. No. 62/788,223 entitled "PLMN Sel ection and Cell (Re) selection on the Unlicensed Spectrum" and attorney docket No. US76276 (hereinafter "US76276 application"), filed on 1/4 of 2019. The disclosure of US76276 application is fully incorporated by reference into the present application.

Technical Field

The present disclosure relates generally to wireless communications, and more particularly to a method and User Equipment (UE) for public land mobile network (Public Land Mobile Network, PLMN) selection and cell (re) selection wireless communications.

Background

Various efforts have been made to improve different aspects (e.g., data rate, delay, reliability, and mobility) of wireless communications of next generation (e.g., fifth generation (5G)) New Radio (NR) wireless communication systems. For example, to achieve higher capabilities and facilitate higher spectrum utilization, next generation wireless communication systems may be implemented to operate on unlicensed spectrum. However, current radio resource control (Radio Resource Control, RRC) _idle or rrc_inactive state-to-rrc_connected state transition procedures (procedures), such as PLMN selection and cell (re) selection procedures, may not be sufficient for a UE to attempt to access a network in a next generation wireless communication system using unlicensed spectrum.

Accordingly, there is a need in the art to provide methods and apparatus for performing PLMN selection and cell (re) selection on one or more unlicensed spectrum.

Disclosure of Invention

The present disclosure relates to a method and a UE for wireless communication for PLMN selection and cell (re) selection.

According to one aspect of the present disclosure, a UE is provided. The UE includes: one or more non-transitory computer-readable media having computer-executable instructions embodied thereon; and at least one processor coupled to the one or more non-transitory computer-readable media. The at least one processor is configured to execute the computer-executable instructions to read system information of a plurality of cells on a first carrier frequency to obtain identification information of a plurality of PLMNs. The first carrier frequency may be an unlicensed carrier frequency. The at least one processor is also configured to execute the computer-executable instructions to: reporting, by an Access Stratum (AS) entity of the UE, the identification information of the plurality of PLMNs to a Non-Access Stratum (NAS) entity of the UE; selecting, by the NAS entity of the UE, one of the plurality of PLMNs as the selected PLMN; during a cell selection procedure, searching the plurality of cells on the first carrier frequency; selecting a suitable cell belonging to the selected PLMN from the plurality of cells on the first carrier frequency as a result of the cell selection procedure; and performing a cell reselection procedure to select a new suitable cell. The cell reselection procedure includes: determining whether a highest ranked cell on the first carrier frequency belongs to one of the selected PLMN and a PLMN indicated as being equivalent to a registered PLMN of the UE; selecting the highest ranked cell as the new suitable cell when the highest ranked cell belongs to one of the selected PLMN and the PLMN indicated as being equivalent to the registered PLMN of the UE; and when the highest ranked cell on the first carrier frequency is not selected as the new suitable cell: prohibiting the highest ranking cell from being selected as the new suitable cell for a first period of time; and iteratively performing a process on the first carrier frequency until the new suitable cell is found on the first carrier frequency or a certain number of cells on the first carrier frequency are determined to be unsuitable cells. The process comprises the following steps: determining whether a next highest ranking cell on the first carrier frequency belongs to one of the selected PLMN and the PLMN indicated as being equivalent to the registered PLMN of the UE; selecting the next highest ranked cell as the new suitable cell when the next highest ranked cell belongs to one of the selected PLMN and the PLMN indicated as being equivalent to the registered PLMN of the UE; and when the next highest ranked cell is not selected as the new suitable cell, determining that the next highest ranked cell is a non-suitable cell.

According to another aspect of the present disclosure, a method of wireless communication is provided. The method comprises the following steps: system information of a plurality of cells is read by the UE on a first carrier frequency to obtain identification information of a plurality of PLMNs. The first carrier frequency may be an unlicensed carrier frequency. The method further comprises the steps of: reporting, by an AS entity of the UE, the identification information of the plurality of PLMNs to a NAS entity of the UE; selecting, by the NAS entity of the UE, one of the plurality of PLMNs as the selected PLMN; searching, by the UE, the plurality of cells on the first carrier frequency during a cell selection procedure; selecting, by the UE, a suitable cell belonging to the selected PLMN from the plurality of cells on the first carrier frequency as a result of the cell selection procedure, and performing, by the UE, a cell reselection procedure to select a new suitable cell. The cell reselection procedure includes: determining whether a highest ranked cell on the first carrier frequency belongs to one of the selected PLMN and a PLMN indicated as being equivalent to a registered PLMN of the UE; selecting the highest ranked cell as the new suitable cell when the highest ranked cell belongs to one of the selected PLMN and the PLMN indicated as being equivalent to the registered PLMN of the UE; and when the highest ranked cell on the first carrier frequency is not selected as the new suitable cell: prohibiting the highest ranking cell from being selected as the new suitable cell for a first period of time; and iteratively performing a process on the first carrier frequency until the new suitable cell is found on the first carrier frequency or a certain number of cells on the first carrier frequency are determined to be unsuitable cells. The process comprises the following steps: determining whether a next highest ranking cell on the first carrier frequency belongs to one of the selected PLMN and the PLMN indicated as being equivalent to the registered PLMN of the UE; selecting the next highest ranked cell as the new suitable cell when the next highest ranked cell belongs to one of the selected PLMN and the PLMN indicated as being equivalent to the registered PLMN of the UE; and when the next highest ranked cell is not selected as the new suitable cell, determining that the next highest ranked cell is a non-suitable cell.

Drawings

Aspects of the disclosure are best understood from the following detailed description when read with the accompanying drawing figures. The various features are not drawn to scale. The dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

Fig. 1 illustrates a flowchart of a method of performing PLMN selection and cell (re) selection procedures on unlicensed spectrum according to an exemplary embodiment of the present disclosure.

Fig. 2A is a schematic diagram illustrating a PLMN selection procedure according to an exemplary embodiment of the present disclosure.

Fig. 2B is a schematic diagram illustrating a cell selection procedure according to an exemplary embodiment of the present disclosure.

Fig. 3 illustrates a flowchart of a method of performing PLMN selection and cell (re) selection procedures on unlicensed spectrum according to an exemplary embodiment of the present disclosure.

Fig. 4A illustrates a flowchart of a cell reselection procedure according to an exemplary embodiment of the present disclosure.

Fig. 4B illustrates a flowchart of a cell reselection procedure according to an exemplary embodiment of the present disclosure.

Fig. 5 illustrates a flowchart of a cell reselection procedure performed when a UE cannot find a new suitable cell on a carrier frequency according to an exemplary embodiment of the present disclosure.

Fig. 6 is a schematic diagram illustrating a cell reselection procedure according to an exemplary embodiment of the present disclosure.

Fig. 7 is a schematic diagram illustrating message flows between an AS entity and a NAS entity of a UE according to an exemplary embodiment of the present disclosure.

Fig. 8 is a block diagram illustrating a node for wireless communication in accordance with various aspects of the disclosure.

Detailed Description

The following description contains specific information pertaining to exemplary embodiments in the present disclosure. The drawings in the present disclosure and their accompanying detailed description are directed to merely exemplary embodiments. However, the present disclosure is not limited to only these exemplary embodiments. Other variations and embodiments of the present disclosure will occur to those skilled in the art. Unless otherwise indicated, like or corresponding elements in the drawings may be indicated by like or corresponding reference numerals. Moreover, the drawings and illustrations in the present disclosure are generally not drawn to scale and are not intended to correspond to actual relative dimensions.

For consistency and ease of understanding, similar features may be identified by the same numerals in the exemplary figures (although not shown in some examples). However, the features in the different embodiments may differ in other respects, and thus should not be narrowly limited to what is shown in the drawings.

The present specification uses the phrases "in one embodiment" or "in some of the present embodiments," which may each refer to one or more of the same or different embodiments. The term "coupled" is defined as connected, whether directly or indirectly through intervening components, and not necessarily limited to physical connections. The term "comprising" when used means "including but not necessarily limited to"; it specifically indicates that the open ended inclusion relationships or membership in the combinations, groups, families, and equivalents so described. The expression "at least one of A, B and C" or "at least one of: A. b and C "means" a alone, or B alone, or C alone, or any combination of A, B and C ".

In addition, for purposes of explanation and not limitation, specific details are set forth such as functional entities, techniques, protocols, standards, etc. to provide an understanding of the described techniques. In other instances, detailed descriptions of well-known methods, techniques, systems, architectures, etc. are omitted so as not to obscure the description with unnecessary detail.

Those skilled in the art will directly recognize that any one or more of the network functions or algorithms described in this disclosure may be implemented in hardware, software, or a combination of software and hardware. The described functions may correspond to modules, which may be software, hardware, firmware, or any combination thereof. The software implementation may include computer-executable instructions stored on a computer-readable medium such as memory or other type of storage device. For example, one or more microprocessors or general purpose computers with communication processing capabilities may be programmed with corresponding executable instructions and implement one or more of the network functions or algorithms described. The microprocessor or general purpose computer may be formed from an application specific integrated circuit (Applications Specific Integrated Circuitry, ASIC), a programmable logic array, and/or using one or more digital signal processors (Digital Signal Processor, DSP). While some of the exemplary embodiments described in this specification are directed to software installed and executed on computer hardware, alternative exemplary embodiments implemented as firmware or as hardware or a combination of hardware and software are well within the scope of the present disclosure.

Computer-readable media includes, but is not limited to, random access Memory (Random Access Memory, RAM), read-Only Memory (Random Access Memory, ROM), erasable programmable read-Only Memory (Erasable Programmable Read-Only Memory, EPROM), electrically erasable programmable read-Only Memory (Electrically Erasable Programmable Read-Only Memory, EEPROM), flash Memory, compact disc read-Only Memory (Compact Disc Read-Only Memory, CD-ROM), magnetic cassettes, magnetic tape, magnetic disk storage devices, or any other equivalent medium capable of storing computer-readable instructions.

A radio communication network architecture, such as a long term evolution (Long Term Evolution, LTE) system, an LTE (LTE-Advanced, LTE-a) upgraded system, an upgraded LTE Pro system, or a 5G NR radio access network (Radio Access Network, RAN), typically includes at least one Base Station (BS), at least one UE, and one or more optional network elements providing connectivity towards the network. The UE communicates with a Network (e.g., core Network (CN), evolved packet Core (Evolved Packet Core, EPC) Network, evolved universal terrestrial radio access Network (Evolved Universal Terrestrial Radio Access Network, E-UTRAN), 5G Core (5G Core,5 gc), or the internet) through a RAN established by one or more BSs.

It should be noted that in the present application, a UE may include, but is not limited to, a mobile station, a mobile terminal or device, a user communication radio terminal. For example, the UE may be a portable radio equipment including, but not limited to, a mobile phone, tablet, wearable device, sensor, vehicle, or personal digital assistant (Personal Digital Assistant, PDA) with wireless communication capabilities. The UE is configured to receive signals from and transmit signals to one or more cells in the radio access network over an air interface.

The BS may be configured to provide communication services according to at least one of the following radio access technologies (Radio Access Technology, RAT): worldwide interoperability for microwave access (Worldwide Interoperability for Microwave Access, wiMAX), global system for mobile communications (Global System for Mobile communications, GSM, commonly referred to as 2G), GSM enhanced data rates for GSM evolution (GSM Enhanced Data rates for GSM Evolution, EDGE) radio access network (Radio Access Network, GERAN), general packet radio service (General Packet Radio Service, GPRS), universal mobile telecommunications system based on basic Wideband code division multiple access (Wideband-Code Division Multiple Access, W-CDMA) (Universal Mobile Telecommunication System, UMTS, commonly referred to as 3G), high speed packet access (High-Speed Packet Access, HSPA), LTE-A, eLTE (evolved LTE, e.g., LTE connected to 5 GC), NR (commonly referred to as 5G) and/or LTE-a Pro. However, the scope of the present application should not be limited to the above-mentioned protocols.

The BSs may include, but are not limited to, node BS (NB) as in UMTS, evolved Node BS (eNB) as in LTE or LTE-a, radio network controllers (Radio Network Controller, RNC) as in UMTS, base station controllers (Base Station Controller, BSC) as in GSM/GERAN, evolved universal terrestrial radio access (Evolved Universal Terrestrial Radio Access, E-UTRA) as in ng-eNB connected to 5GC, next generation Node BS (next generation Node B, gNB) as in 5G-RAN, and any other device capable of controlling radio communications and managing radio resources within a cell. The BS may serve one or more UEs over the radio interface.

The BS is operable to provide radio coverage to a particular geographical area using a plurality of cells forming a radio access network. The BS supports the operation of the cell. Each cell is operable to provide service to at least one UE within its radio coverage area. More specifically, each cell (often referred to as a serving cell) provides services to serve one or more UEs within its radio coverage (e.g., each cell schedules downlink resources and optionally uplink resources to at least one UE within its radio coverage for downlink packet transmission and optionally uplink packet transmission). The BS may communicate with one or more UEs in a radio communication system through a plurality of cells. The cell may allocate Sidelink (SL) resources for supporting proximity services (Proximity Service, proSe) or internet of vehicles (Vehicle to Everything, V2X) services. Each cell may have a coverage area that overlaps with other cells.

As discussed above, the frame structure of NR is to support flexible configuration for accommodating various next generation (e.g., 5G) communication requirements, such as enhanced mobile broadband (Enhanced Mobile Broadband, emmbb), large-scale machine type communication (Massive Machine Type Communication, emtc), ultra-Reliable and Low-latency communication (URLLC), while meeting high reliability, high data rate and Low latency requirements. Such as the third generation partnership project (the 3 ^rd Generation Partnership Project,3 GPP) orthogonal frequency division multiplexing (Orthogonal Frequency-Division Multiplexing, OFDM) techniques agreed upon in the 3 GPP) can be used as a reference for the NR waveforms. An extensible OFDM digital scheme such as adaptive subcarrier spacing, channel bandwidth and Cyclic Prefix (CP) may also be used. In addition, two coding schemes are considered for NR: (1) A Low-Density Parity-Check (LDPC) code and (2) a polarity code. The coding scheme adaptation may be configured based on channel conditions and/or service applications.

Furthermore, it is also contemplated that at least Downlink (DL) transmission data, guard periods and Uplink (UL) transmission data should be included in the transmission time interval TX of a single NR frame, wherein the respective parts of DL transmission data, guard periods, UL transmission data should also be configurable, e.g. based on NR network dynamics. Further, SL resources may also be provided in NR frames to support ProSe services or V2X services.

Furthermore, the terms "system" and "network" may be used interchangeably herein. The term "and/or" is used herein merely to describe the association of associated objects and indicates that there may be three relationships. For example, a and/or B may indicate: a is present alone, A and B are present simultaneously, or B is present alone. Furthermore, the character "/" herein generally means that the former and latter associated objects are in an "or" relationship.

On the licensed spectrum, the UE may perform a PLMN selection procedure based on signal strength of the cell, e.g., measured reference signal received power (Reference Signal Received Power, RSRP) from the cell. Cells on the licensed spectrum may broadcast identification information of the PLMN (e.g., PLMN Identity (ID)) and a preconfigured PLMN for the UE. On each licensed carrier frequency, the AS entity of the UE may report the PLMN ID broadcast by the cell with the strongest signal strength to the NAS entity of the UE. In general, cells operating on a common licensed carrier frequency may belong to the same PLMN.

There may be multiple PLMNs operating on one carrier frequency. For example, one or more Unlicensed RAT technologies (e.g., standalone New Radio-Unlicensed (NR-U)) may be introduced, meaning that multiple PLMNs may operate their own cells on the same Unlicensed spectrum. Accordingly, there is a need to provide PLMN selection and cell (re) selection procedures on unlicensed spectrum, especially considering the uncertainty of channel loading and channel sharing among multiple PLMNs. In another example, if RAN sharing is considered, one or more PLMNs may operate on the same carrier frequency. The one or more PLMNs may be one or more public PLMNs and/or one or more private PLMNs. Accordingly, there is a need to provide PLMN selection and cell (re) selection procedures when multiple PLMNs are operating on one carrier frequency. In the RAN sharing case, one RAN (or one cell) may be shared and operated by a plurality of PLMNs.

In some embodiments, if the best cell does not belong to the selected PLMN or registered PLMN (or equivalent PLMN), the UE may camp on a non-best cell on a carrier frequency (e.g., unlicensed carrier frequency). The best cell may be the highest ranked cell of the cells on the same carrier frequency. Cells on a carrier frequency may be ranked by received radio signal quality and/or one or more other measured values. For example, the best cell (or highest ranked cell) may be the cell on the carrier frequency with the best received radio signal quality, while the non-best cell (or non-highest ranked cell or lower ranked cell) may be a cell on the carrier frequency other than the best cell.

It should be noted that terms such as "best cell", "strongest cell", and "highest ranking cell" may be interchangeable in some of the present embodiments. Similarly, terms such as "non-best cell", "non-strongest cell", "lower ranked cell", and "non-highest ranked cell" may be interchangeable in some of the present embodiments.

In some embodiments, all cells on one licensed carrier frequency may belong to the same (equivalent) PLMN. Thus, after PLMN selection, the licensed carrier frequency may be indirectly selected. The UE may then prioritize cells and camp on the strongest cell on the licensed carrier frequency. Unlike licensed spectrum operation, one or more of the cells sharing the same unlicensed carrier frequency may belong to different PLMNs. If the UE prioritizes cells and camps on the strongest cell on an unlicensed carrier frequency after PLMN selection, the UE may waste time and consume additional power to search for a suitable cell when the strongest cell does not belong to the selected/registered/equivalent PLMN. In view of this, PLMN selection and cell (re) selection methods for unlicensed spectrum operation are provided in at least some of the embodiments of the invention.

It should be noted that the PLMN selection and cell (re) selection methods described herein are also applicable to licensed spectrum operation.

Fig. 1 illustrates a flowchart of a method of performing PLMN selection and cell (re) selection procedures on unlicensed spectrum according to an exemplary embodiment of the present disclosure. As shown in fig. 1, the method includes acts 102, 104, 106, 108, and 110, where acts 102, 104, and 106 may be performed during a PLMN selection procedure and acts 108 and 110 may be performed during a cell selection procedure.

In act 102, the UE may read system information for a plurality of cells on a first carrier frequency to obtain identification information for a plurality of PLMNs. In some of the present embodiments, the first carrier frequency may be an unlicensed carrier frequency. The plurality of cells may include a strongest cell and a non-strongest cell. Each cell may broadcast the identification information of multiple PLMNs in system information (e.g., system information block 1 (System Information Block, sib1)).

In act 104, the AS entity of the UE may report identification information of the multiple PLMNs to the NAS entity of the UE. PLMNs identified by the identification information of the plurality of PLMNs reported from the AS entity of the UE to the NAS entity of the UE may refer to found PLMNs of the UE. The NAS entity of the UE may be used to provide upper layer signaling (e.g., NAS signaling) between the UE and the core network, and the AS entity of the UE may be used to provide lower layer signaling (e.g., RRC signaling) between the RAN and the UE. For example, the AS entity may be used to transmit data over the wireless connection and to manage radio resources. The AS entity may include one or more layers, such AS a protocol stack (protocol stack), including a Physical (PHY) layer, a medium access control (Medium Access Control, MAC) layer, a radio link control (Radio Link Control, RLC) layer, a packet data convergence protocol (Packet Data Convergence Protocol, PDCP) layer, a service data adaptation protocol (Service Data Adaptation Protocol, SDAP) layer, and an RRC layer. Each of the AS entity and the NAS entity of the UE may be implemented using electronic hardware, computer software, or any combination thereof.

In act 106, the NAS entity of the UE may select one of the plurality of PLMNs as the selected PLMN. For example, the NAS entity of the UE may maintain or store a list of registered/equivalent/subscribed PLMNs and select a PLMN mapped to the list as a result of a PLMN selection procedure (e.g., the selected PLMN).

In act 108, the UE may search for multiple cells on the first carrier frequency during a cell selection procedure. During the cell selection procedure, the UE may search not only for the strongest cell but also for additional cells on the first carrier frequency. In some implementations, the additional cells may or may not have a signal strength above a threshold (e.g., RSPP, reference signal received quality (Reference Signal Received Quality, RSRQ)) (e.g., the additional cells may satisfy the S criteria). The plurality of cells may be searched based on certain (pre) configurations or predefined rules. For example, the plurality of cells may be the N strongest (e.g., first N) cells on the first carrier frequency, where N is a positive integer. In some of the present embodiments, the value of N may be predefined (e.g., defined by 3GPP specifications), preconfigured to the UE (e.g., stored in a universal subscriber identity module (Universal Subscriber Identity Module, USIM) and/or stored in a universal integrated circuit card (Universal Integrated Circuit Card, UICC)), configured by one or more cells (e.g., via system information and/or via dedicated signaling), or determined based on the UE implementation.

In act 110, the UE may select a suitable cell from the plurality of cells that belongs to the selected PLMN as a result of the cell selection procedure on the first carrier frequency. The suitable cell may or may not be the strongest cell on the first carrier frequency.

Fig. 2A is a schematic diagram illustrating a PLMN selection procedure according to an exemplary embodiment of the present disclosure. Fig. 2B is a schematic diagram illustrating a cell selection procedure according to an exemplary embodiment of the present disclosure.

In fig. 2A, there are K cells C1, C2, C3, … …, and CK on the carrier frequency f 1. In the exemplary embodiment as illustrated in fig. 2A and 2B, the carrier frequency f1 may be an unlicensed carrier frequency. However, this is for illustration purposes only and is not intended to limit the scope of the present invention. In some other embodiments, carrier frequency f1 may be a licensed carrier frequency.

Each cell on carrier frequency f1 may broadcast in system information (e.g., SIB 1) its identification information for one or more PLMNs. For example, the cell C1 may broadcast the PLMN ID #1 of the PLMN #1 to which the cell C1 belongs; cell C2 may broadcast PLMN id#2 of plmn#2 to which cell C2 belongs; cell C3 may broadcast PLMN ID #3 of PLMN #3 to which cell C3 belongs; and the cell CK may broadcast PLMN ID #2 of PLMN #2 to which the cell CK belongs. If a cell belongs to more than one PLMN, the cell may broadcast corresponding PLMN identification information in system information (e.g., SIB 1).

In an example embodiment, cells C1 through CK may be ranked by the UE based on received radio signal quality (e.g., RSPP and/or RSRQ), e.g., from strongest to weakest. The UE may read the system information of the N1 strongest cells on carrier frequency f 1. The UE may obtain the identification information of the PLMN from system information broadcast by these cells (e.g., N1 strongest cells). In some of the present embodiments, the value of N1 may be predefined (e.g., defined by 3GPP specifications), preconfigured to the UE (e.g., stored in the USIM and/or stored in the UICC), configured by one or more cells (e.g., via system information and/or via dedicated signaling), or determined based on the UE implementation. For example, if n1=3, then the N1 strongest cells may include cells C1, C2, and C3, where cell C1 may be the highest ranked cell on carrier frequency f1, followed by cell C2 (the next (e.g., second) highest ranked cell), and then cell C3 (the next highest ranked cell after cell C2, or the third highest ranked cell). The UE may obtain the identification information (e.g., including PLMN ID #1, PLMN ID #2, and PLMN ID # 3) of PLMNs from cells C1, C2, and C3 from the broadcast system information of cells C1, C2, and C3. The AS entity of the UE may report a list of available/found PLMNs (e.g., including PLMN ID #1, PLMN ID #2, and PLMN ID # 3) to the NAS entity of the UE for PLMN selection. The NAS entity of the UE may then select one of the reported available/found PLMNs as a result of the PLMN selection procedure. For example, PLMN #2 may be selected because it maps to one PLMN in the list maintained or stored by the UE. In one embodiment, the UE may read system information for N4 strongest cells on carrier frequency f1, where the signal strength of the N4 strongest cells may be above a threshold (e.g., satisfy an S criterion). The UE may obtain the identification information of the PLMN from the system information broadcast by these cells (e.g., the N4 strongest cells). In some of the present embodiments, the value of N4 may be predefined (e.g., defined by 3GPP specifications), preconfigured to the UE (e.g., stored in the USIM and/or stored in the UICC), or configured by one or more cells (e.g., via system information and/or via dedicated signaling), making decisions based on the UE implementation. In one embodiment, if the UE can find N0 strongest cells, where N0 is less than N1 in the case of N1 strongest cells or N0 is less than N4 in the case of N4 strongest cells, the UE can obtain the identification information of the PLMN from the system information broadcast by these cells (e.g., N0 strongest cells). The AS entity of the UE may report a list of available/found PLMNs (e.g., including the obtained identification information of the PLMNs) to the NAS entity of the UE for PLMN selection. The NAS entity of the UE may then select one of the reported available/found PLMNs as a result of the PLMN selection. In some of the present embodiments, if the UE cannot select a PLMN, or if the UE cannot select a suitable cell, the UE may de-prioritize the carrier frequency when the UE performs PLMN selection or cell (re) selection on the carrier frequency based on the N0 or N1 configuration.

Once the PLMN is selected, the UE may perform a cell selection procedure to search for a suitable cell to camp on. For example, the UE may search for N2 strongest cells on carrier frequency f1, where N2 is a positive integer. In some of the present embodiments, the value of N2 may be predefined (e.g., defined by 3GPP specifications), preconfigured to the UE (e.g., stored in the USIM and/or stored in the UICC), configured by one or more cells (e.g., via system information and/or via dedicated signaling), or determined based on UE implementation. As shown in fig. 2B, if n2=3, the N2 strongest cells may include cells C1, C2, and C3. Cell C1 may be the highest ranked cell on carrier frequency f1, followed by cell C2 (the next (e.g., second) highest ranked cell), and then cell C3 (the next highest ranked cell after cell C2, or the third highest ranked cell).

As described above, each of cells C1, C2, and C3 may broadcast the identification information of its corresponding one or more PLMNs in system information (e.g., SIB 1). Based on the system information, the UE may know that cells C1, C2 and C3 belong to plmn#1, plmn#2 and plmn#3, respectively, which means that the N2 strongest cells on carrier frequency f1 belong to different PLMNs. The UE may determine whether a suitable cell may be found among the N2 strongest cells (e.g., cells C1, C2, and C3) on carrier frequency f1 by checking whether these cells belong to the selected PLMN or are indicated as equivalent PLMNs to the registered PLMNs of the UE. As illustrated in fig. 2B, cell C2 may be selected as the appropriate cell for the UE to camp on, since cell C2 has the strongest/best received radio signal quality (e.g., RSRP and/or RSRQ) among all cells (e.g., cells C2 and CK) belonging to the selected PLMN (e.g., PLMN # 2) on carrier frequency f 1. In one embodiment, cell C2 may be selected as the appropriate cell for the UE to camp on, since cell C2 is the highest ranked cell among the cells (e.g., cells C2 and CK) belonging to the selected PLMN (e.g., PLMN # 2).

It should be noted that even though the values of N1 and N2 are the same in the exemplary embodiment, in some of the present embodiments, the values of N1 and N2 may be independently (pre) configured. In some other embodiments, the value of N2 may depend on the value of N1. N2 may or may not have the same value as N1.

In some of the present embodiments, one or more values of one or more of N1, N2, N0, and N4 may be independently (pre) configured. In some other embodiments, the value of one of N1, N2, N0, and N4 may depend on the value of another of N1, N2, N0, and N4.

Fig. 3 illustrates a flowchart of a method of performing PLMN selection and cell (re) selection procedures on unlicensed spectrum according to an exemplary embodiment of the present disclosure. As shown in FIG. 3, the method includes acts 302, 304, 306, and 308.

In act 302, the UE may perform a PLMN selection procedure to select a PLMN.

In act 304, the UE may perform a cell selection procedure to select a suitable cell to camp on. The appropriate cell may belong to the selected PLMN.

In act 306, the UE may determine whether the selected suitable cell meets a cell reselection criterion (e.g., R criterion). The cell reselection criteria may relate to a change in measured value of a suitable cell (e.g., S criteria). For example, once the signal quality of the selected suitable cell deteriorates and deteriorates below a predetermined threshold, the cell reselection criterion may be met and the UE is triggered to perform a cell reselection procedure to find a new suitable cell, as illustrated by act 308. Conversely, in act 306, if the selected suitable cell does not meet the cell reselection criteria, the UE may continue to detect whether the current suitable cell meets the cell reselection criteria, as illustrated in fig. 3. It should be noted that when the UE reselects a new suitable cell in act 308, the method may return to act 306, where the UE may continue to determine whether the reselected suitable cell meets cell reselection criteria (e.g., R criteria).

In one embodiment, when the UE camps on a cell (e.g., a suitable cell selected during a cell (re) selection procedure), the UE may periodically search for a better cell according to a cell re-selection criteria. If the UE finds a better cell, the UE may select the better cell as the appropriate cell to camp on. In one embodiment, the UE may reselect a new suitable cell if at least one of two conditions is met: (1) According to the cell reselection criteria during the time interval, the new suitable cell is better than the currently serving/camping cell, and (2) more than 1 second has elapsed since the UE camps on the currently serving/camping cell.

Fig. 4A illustrates a flowchart of a cell reselection procedure according to an exemplary embodiment of the present disclosure.

In act 402, the UE may determine whether the highest ranked cell on the first carrier frequency belongs to the selected PLMN or registered PLMN (or equivalent PLMN) of the UE.

If the result of act 402 is "yes," the UE may select the highest ranked cell as the new suitable cell in act 404. In this case, the UE may switch from the initial suitable cell to a new suitable cell to camp on. Conversely, if the result of act 402 is "no," the UE may prohibit the highest ranked cell from being selected as the new suitable cell for the period of time Ta in act 406. The length of Ta may be preconfigured in the UE or configured by one or more cells (e.g., via system information and/or via dedicated signaling). In one embodiment, the maximum value of Ta may be 300 seconds.

In act 408, when the highest ranked cell is not selected by the UE as the appropriate cell to camp on, the UE may further determine whether the next highest ranked (e.g., second highest ranked) cell on the first carrier frequency belongs to the selected PLMN or registered PLMN (or equivalent PLMN) of the UE.

As described above, cells on a carrier frequency may be ranked by their corresponding measured metric values. For example, the highest ranked cell and the next highest ranked cell on the first carrier frequency may be ranked by received radio signal quality (e.g., RSPP, RSRQ). In this case, the next highest ranked cell may have a poorer received radio signal quality than the highest ranked cell.

In act 410, when it is determined in act 408 that the next highest ranked cell belongs to the selected PLMN or registered PLMN (or equivalent PLMN) of the UE, the UE may select the next highest ranked cell as the new suitable cell. In this case, the new suitable cell (belonging to the selected PLMN or indicated as being equivalent to the registered PLMN of the UE) may be a non-highest ranked (e.g. lower ranked) cell of all cells on the first carrier frequency.

In act 412, when the next highest ranked cell does not belong to the selected PLMN or registered PLMN (or equivalent PLMN) of the UE as determined in act 408, the UE may determine that the next highest ranked cell is an unsuitable cell. In one embodiment, when the next highest ranked cell is determined to be an unsuitable cell, the UE may prohibit selection of the next highest ranked cell as a new suitable cell for the period of time Tb. The length of the Tb may be preconfigured in the UE (e.g., stored in the USIM and/or in the UICC) or configured by one or more cells (e.g., via system information and/or via dedicated signaling). In one embodiment, the maximum value of Tb may be 300 seconds.

In act 414, the UE may determine whether the total number of unsuitable cells on the first carrier frequency reaches a certain number. In an exemplary embodiment, the specific number of values may be a positive integer. In some of the present embodiments, the specific number may be predefined (e.g., defined by 3GPP specifications), preconfigured to the UE (e.g., stored in the USIM and/or stored in the UICC), configured by one or more cells (e.g., via system information and/or via dedicated signaling), or determined based on the UE implementation.

If the result of act 414 is "yes," then the program may go to node A, continuing to node A' in FIG. 5. If the result of act 414 is "no," the procedure may return to act 408, where the UE may determine whether the next highest ranked cell belongs to the selected PLMN or registered PLMN (or equivalent PLMN) of the UE. In one embodiment, the term "next highest ranked cell" may refer to a cell that is ranked after the ranking of the cell that has just been checked for non-selection.

In an exemplary embodiment, when the highest ranked cell is not selected as a suitable cell, the UE may iteratively perform a process (process) on the first carrier frequency until a new suitable cell is found on the first carrier frequency or a certain number of cells on the first carrier frequency are determined to be unsuitable cells. As illustrated in fig. 4, acts 408, 412, and 414 may be performed in multiple iterations if the UE has not been able to find a new suitable cell on the first carrier frequency.

Fig. 4B illustrates a flowchart of a cell reselection procedure according to another exemplary embodiment of the present disclosure.

In act 420, the UE may determine whether the highest ranked cell of all non-barred cells on the first carrier frequency belongs to the selected PLMN or registered PLMN (or equivalent PLMN) of the UE. The non-barred cell may be a new suitable cell that is not currently barred from being selected for the UE to camp on. The forbidden cell may be a new suitable cell that is currently forbidden to be selected (e.g., via a cell-specific timer) for the UE to camp on.

If the result of act 420 is "yes," the UE may select the highest ranked cell as the new suitable cell in act 422. In this case, the UE may switch from the initial suitable cell to a new suitable cell to camp on. Conversely, if the result of act 420 is "no," the UE may prohibit the highest ranked cell from being selected as the new suitable cell for a period of time (e.g., ta) in act 424. The length of Ta may be preconfigured in the UE (e.g., stored in the USIM and/or in the UICC) or by one or more cells (e.g., via system information and/or via dedicated signaling). In one embodiment, the maximum value of Ta may be 300 seconds.

In act 426, the UE may determine that the highest ranked cell is an unsuitable cell because the highest ranked cell does not belong to the selected PLMN or registered PLMN (or equivalent PLMN) of the UE.

In act 428, the UE may determine whether the total number of unsuitable cells on the first carrier frequency reaches a particular number. In an exemplary embodiment, the specific number of values may be a positive integer. In some of the present embodiments, the specific number may be predefined (e.g., defined by 3GPP specifications), preconfigured to the UE (e.g., stored in the USIM and/or stored in the UICC), configured by one or more cells (e.g., via system information and/or via dedicated signaling), or determined based on the UE implementation.

If the result of act 428 is "yes," then the program may go to node A, continuing to node A' in FIG. 5. If the result of act 428 is "NO," then the program may return to act 420.

In some of this embodiment, act 428 may be omitted. In such cases, once the highest ranked cell is determined to be an unsuitable cell in act 426, the procedure may proceed directly to node a. In some other implementations, actions 424, 426, and 428 may be omitted. In such cases, if the result of act 420 is "no," the procedure may proceed directly to node a.

Fig. 5 illustrates a flowchart of a cell reselection procedure performed when a UE cannot find a new suitable cell on a first carrier frequency according to an exemplary embodiment of the present disclosure. It should be noted that while acts 502 and 504 are depicted as separate acts that are represented in fig. 5 as separate blocks, these separately depicted acts should not be construed as necessarily order dependent. The order in which the acts are performed in fig. 5 is not intended to be construed as a limitation, and any number of the described blocks may be combined in any order to implement the described methods or alternative methods. Further, in some of the present embodiments, at least one of acts 502 and 504 may be omitted during the cell reselection procedure.

In an exemplary embodiment, when the UE finds that the total number of unsuitable cells on the first carrier frequency reaches a certain number, the cell reselection procedure may continue to node a' of fig. 5. Next in act 502, for a cell reselection procedure, the UE may de-prioritize (de-prioritize) a first carrier frequency among a set of carrier frequencies over a period of time (e.g., tc). For example, the UE may search for a new suitable cell on a different carrier frequency during a cell reselection procedure, where each carrier frequency may be assigned a corresponding reselection priority. Once the first carrier frequency is de-prioritized (e.g., the reselection priority of the first carrier frequency is reduced), the UE may prefer another carrier frequency with a higher reselection priority than the first carrier frequency in order to search for a new suitable cell on the selected carrier frequency during a later cell reselection procedure. In one embodiment, once the UE de-prioritizes a first carrier frequency of a set of carrier frequencies for a cell reselection procedure, the UE may consider the first carrier frequency as having a lowest priority among the set of carrier frequencies. In some of the present embodiments, the length of Tc may be preconfigured in the UE or configured by one or more cells (e.g., via system information and/or via dedicated signaling). Tc may or may not have the same value as Ta.

In act 504, the UE may search for a new suitable cell on the second carrier frequency. In some of the present embodiments, the second carrier frequency may be an unlicensed carrier frequency. In some other embodiments, the second carrier frequency may be a licensed carrier frequency. In one embodiment, after the UE de-prioritizes the first carrier frequency, the second carrier frequency may have a highest priority among the set of carrier frequencies for a cell reselection procedure.

Fig. 6 is a schematic diagram illustrating a cell reselection procedure according to an exemplary embodiment of the present disclosure. As illustrated in fig. 6, cells C5, C3, and C1 on carrier frequency f1 may be ranked from strongest to weakest in terms of received radio signal quality (e.g., RSPP and/or RSRQ). Thus, cell C5 may be the highest ranked cell on carrier frequency f1, followed by cell C3, and then cell C1. It should be noted that the ranking of cells on carrier frequency f1 may be different compared to fig. 2A and 2B, as channel/network conditions may change over time.

In an exemplary embodiment, cells C5, C3, and C1 may broadcast in system information (e.g., SIB 1) the identification information (e.g., PLMN ID #5, PLMN ID #3, and PLMN ID # 1) of their corresponding PLMNs. Based on the system information, the UE may know that C5, C3, and C1 belong to plmn#5, plmn#3, and plmn#1, respectively. If the selected/registered/equivalent PLMN is PLMN #2, the UE may determine that cell C5 (the highest ranked cell on carrier frequency f 1) is a non-suitable cell because cell C5 does not belong to PLMN #2. For the same reason, the UE may also determine that cells C3 and C1 are unsuitable cells. Since the UE cannot find a new suitable cell from the N3 strongest cells (when n3=3) on carrier frequency f1, the UE may then search for a new suitable cell on another carrier frequency f2, which may be an licensed carrier frequency or an unlicensed carrier frequency.

On carrier frequency f2, the UE may follow the methods illustrated in fig. 4 and 5 to continue the cell reselection procedure. For example, the UE may determine whether the highest ranked cell on carrier frequency f2 belongs to the selected PLMN or is indicated as being equivalent to the registered PLMN of the UE. If the result of the determination is "yes," the UE may select the highest ranked cell on carrier frequency f2 as the new suitable cell. Conversely, if the result of the determination is "no," the UE may prohibit the selection of the highest ranked cell on carrier frequency f2 as the new suitable cell for a period of time (Td). In some of the present embodiments, td and Ta may be independently (pre) configured such that the length of Td may be independent of the length of Ta. In some other embodiments, the length of Td may depend on the length of Ta. Td may or may not have the same length as Ta. In one embodiment, the maximum value of Td may be 300 seconds.

In some of the present embodiments, when the highest ranked cell on carrier frequency f2 is not selected as a new suitable cell, the UE may iteratively perform the procedure on carrier frequency f2 until a new suitable cell is found from the N3' strongest cells on carrier frequency f2 or the total number of unsuitable cells on carrier frequency f2 reaches N3', where N3' is a positive integer. In some of the present embodiments, the value of N3' may be predefined (e.g., defined by 3GPP specifications), preconfigured to the UE (e.g., stored in the USIM and/or stored in the UICC), configured by one or more cells (e.g., via system information and/or via dedicated signaling), or determined based on the UE implementation. In some of the present embodiments, the value of N3' may be independent of the value of N3. In some other embodiments, the value of N3' may depend on the value of N3. N3' may or may not have the same value as N3. In one embodiment, the UE may not read system information from all N3' strongest cells until the UE finds a new suitable cell on carrier frequency f2 and camps on the cell. Once the UE finds a new suitable cell on carrier frequency f2 and camps on that cell, the UE may not further read system information from the next highest ranked cell that is ranked after the new suitable cell's ranking. Once the UE finds a new suitable cell on carrier frequency f2 and camps on that cell, the UE may not further measure the received radio signal quality of the remaining other cells on carrier frequency f2 for this cell reselection procedure. Once the UE finds a new suitable cell on carrier frequency f2 and camps on that cell, the UE may not further rank the remaining other cells on carrier frequency f2 for this cell reselection procedure.

As illustrated in fig. 6, if N3 '=3, the N3' strongest cells may include cells C4, C6, and C2, where cell C4 may be the highest ranked cell on carrier frequency f2, followed by cell C6, and then cell C2. Cells C4, C6, and C2 may broadcast the identification information (e.g., PLMN ID #4, PLMN ID #6, and PLMN ID # 2) of their corresponding PLMNs in system information (e.g., SIB 1). Based on the system information, the UE can know that C4, C6 and C2 belong to plmn#4, plmn#6 and plmn#2, respectively, and reselect cell C2 as a new suitable cell because cell C2 belongs to the selected plmn#2.

Fig. 7 is a schematic diagram illustrating message flows between an AS entity of a UE and a NAS entity of the UE according to an exemplary embodiment of the present disclosure.

AS illustrated in fig. 7, in act 702, NAS entity 73 of the UE may provide a message to AS entity 71 of the UE. The message may indicate which of one or more PLMN types the UE supports. Based on the message, the AS entity 71 may or may not modify the list of available PLMNs to be reported to the NAS entity 73. For example, AS entity 71 may filter out some PLMNs of PLMN types that the UE does not support from the list of PLMNs to be reported to NAS entity 73. In some of the present embodiments, the one or more PLMN types may include a public PLMN type, a private PLMN type, and public and private PLMN types. In one embodiment, if the NAS entity 73 of the UE does not provide a message to the AS entity 71 of the UE, it means that the UE supports (or needs) selection of a public PLMN AS a result of PLMN selection. In one embodiment, if the NAS entity 73 of the UE provides a message to the AS entity 71 of the UE, and if the message includes a first indicator corresponding to the private PLMN type, it means that the UE supports (or needs) the private PLMN AS a result of PLMN selection. In one embodiment, if the NAS entity 73 of the UE provides a message to the AS entity 71 of the UE, and if the message includes a second indicator corresponding to a public and private PLMN type, it means that the UE supports (or needs) the public or private PLMN AS a result of PLMN selection.

As mentioned above, multiple networks (e.g., PLMNs) may operate on unlicensed or licensed spectrum. Further, multiple networks (e.g., PLMNs) may share the same unlicensed carrier or the same licensed carrier. Each network may be public, private, or both public and private. The public network (e.g., public PLMN) may be provided by, but is not limited to, an operator or virtual operator, which may provide radio services to public users. The public network may possess one or more licensed spectrum and also support radio access technologies on the one or more licensed spectrum. Public networks may also support radio access technologies on unlicensed spectrum. On the other hand, private networks (e.g., private PLMNs) may be provided by, but are not limited to, micro-operators, factories, or businesses that may provide radio services to their private users (e.g., employees or machines). The private network may support radio access technologies on one or more unlicensed spectrum. If the private PLMN has a licensed spectrum, the corresponding private network may also support radio access technologies on the licensed spectrum.

It should be noted that even though the term "public PLMN" may be used in some of the present embodiments, such term may be replaced by another term "public network" as the techniques described herein are not intended to be limited to one or more public PLMNs and may be applicable to one or more other types of public networks. Similarly, even though the term "private PLMN" may be used in some of the present embodiments, such term may be replaced by another term such as "private network" or "non-public network" (NPN) because the techniques described herein are not intended to be limited to one or more private PLMNs and may be applicable to one or more other types of private/non-public networks. In one embodiment, the private Network scenario may be a Stand-alone Non-Public Network (SNPN), i.e. operated by an NPN operator and independent of the Network functions provided by the (Public) PLMN. In another embodiment, the NPN scenario may be an NPN (Public network integrated NPN, PNI-NPN) of an integrated public network, i.e. a non-public network deployed with support of a (public) PLMN. One or more SNPN may be identified by a PLMN ID and/or Network ID (NID) broadcast in SIB1 of a cell supporting the SNPN. The PNI-NPN may be identified by a PLMN ID and/or a cell access group (Cell Access Group, CAG) ID broadcast with SIB1 of a cell supporting the PNI-NPN. The identification information of the SNPN (e.g., the SNPN ID) may include a PLMN ID and/or NID. The identification information of the PNI-NPN (e.g., PNI-NPN ID) may include a PLMN ID and/or a CAG ID. Each of the PLMN ID, SNPN ID, and PNI-NPN ID may be referred to as a PLMN-related ID. In some of the present embodiments, the PLMN-related ID may be included in the identification information of the PLMN.

In some of the present embodiments, the public PLMN and the private PLMN may support several deployment scenarios. For example, a deployment scenario may include carrier aggregation between licensed bands (e.g., NR for Primary Cell (PCell)) and unlicensed bands (e.g., NR-U for Secondary Cell (SCell)), where an unlicensed SCell may have both DL and UL, or only DL; a dual connection (or multiple connections) between radio access technologies on licensed bands (e.g., LTE, NR for PCell) and radio access technologies on unlicensed bands (e.g., NR-U for primary and secondary cells (Primary Secondary Cell, PSCell)); dual connectivity (or multiple connectivity) between licensed bands (e.g., LTE for PCell) and standalone radio access technologies on unlicensed bands (e.g., standalone NR-U); NR cells with DL in unlicensed band and UL in licensed band; and a standalone unlicensed-radio access technology (e.g., standalone NR-U). In some of the present embodiments, the private PLMN may primarily support, but is not limited to, standalone unlicensed radio access technologies (e.g., standalone NR-U).

During the PLMN selection procedure, the AS entity of the UE may in some of the present embodiments report available PLMNs to the NAS entity of the UE upon request from the NAS entity of the UE or automatically. In some of the present embodiments, the NAS entity of the UE may inform the AS entity of the UE of which PLMN type (e.g., public, private, public and private) the UE supports (AS illustrated in fig. 7).

In some of the present embodiments, the AS entity of the UE may be preconfigured with information of which PLMN type (e.g., public, private, public, and private) the UE supports. In some of the present embodiments, if the UE supports only public PLMNs, the AS entity of the UE may report available public PLMNs to the NAS entity of the UE. In some of the present embodiments, if the UE supports only private PLMNs, the AS entity of the UE may report available private PLMNs to the NAS entity of the UE. In some of the present embodiments, if the UE supports public PLMNs and private PLMNs, the AS entity of the UE may report available public PLMNs and/or private PLMNs to the NAS entity of the UE.

In some of the present embodiments, the public PLMN and the private PLMN may use the same mobile country code (Mobile Country Code, MCC) but different mobile network codes (Mobile Network Code, MNC). In some of the present embodiments, if multiple PLMNs share the same MCC, then the cell may transmit both the MCC and MNC of one of the PLMNs (e.g., via system information and/or via dedicated signaling) and transmit only the MNC of the other PLMN (where the MCC is absent).

In some of the present embodiments, a cell may broadcast identification information of one or more PLMNs of other cells operating on the same carrier frequency (e.g., on unlicensed carrier frequencies). For example, one or more PLMNs may be referred to as "one or more neighboring PLMNs". The UE may read the identification information broadcast by the cell (e.g., in SIB1 or other system information (System Information, SI)) and obtain one or more PLMN IDs of one or more neighboring PLMNs of the cell operating on the same carrier frequency. The AS entity of the UE may report the found one or more PLMN IDs to the NAS entity of the UE, the one or more PLMN IDs including identification information of PLMNs operating this cell and identification information of PLMNs operating neighboring cells on the same carrier frequency. The NAS entity of the UE may then select a PLMN based on the reported one or more PLMN IDs as a result of the PLMN selection procedure.

In some of the present embodiments, system information from one or more cells on a carrier frequency (e.g., licensed carrier frequency, unlicensed carrier frequency) may include PLMN type information indicating at least one PLMN type (e.g., public, private, or both public and private) associated with the cell. For example, cells on unlicensed spectrum may broadcast an indicator to indicate that the cells are shared by a public PLMN, a private PLMN, or both public and private PLMNs. In some of the present embodiments, each PLMN ID broadcast by a cell may be accompanied by an indicator to indicate the PLMN type associated with the corresponding PLMN ID. For example, a cell may broadcast several PLMN lists. One PLMN list may include PLMN IDs of public PLMNs, one PLMN list may include PLMN IDs of private PLMNs, and one PLMN list may include PLMN IDs of both public and private PLMNs.

In some of the present embodiments, the cell may broadcast one or more indicators and identification information (e.g., one or more PLMN ID lists) of one or more PLMNs via SIB1 or other SI. If there are no additional indicators broadcast by cells operating on unlicensed spectrum, the UE may default to consider PLMNs identified by broadcast identification information (e.g., a PLMN ID list) of one or more PLMNs as public PLMNs. In some of the present embodiments, if the UE supports only public PLMNs, the AS entity of the UE may consider the public PLMN IDs broadcast by the cell AS candidate available PLMNs. In some of the present embodiments, if the UE supports only private PLMNs, the AS entity of the UE may consider private PLMN IDs (e.g., PLMN IDs and/or NIDs, PLMN IDs, and/or CAG IDs) broadcast by the cell AS candidate available PLMNs. In some of the present embodiments, if the UE supports both public and private PLMNs, the AS entity of the UE may consider both public and private PLMN IDs broadcast by the cell AS candidate available PLMNs. In some of the present embodiments, the AS entity of the UE may select an available PLMN from among candidate available PLMNs based on predefined rules. For example, if the signal quality of the cell broadcasting the identification information of one or more candidate available PLMNs meets a high quality criterion, one or more candidate available PLMNs may be selected as one or more available PLMNs. The AS entity of the UE may report one or more available PLMNs to the NAS entity of the UE for PLMN selection.

In some of the present embodiments, on each unlicensed carrier frequency, the UE may search for N strongest cells (e.g., N1 strongest cells, N2 strongest cells, N3 strongest cells, or N3' strongest cells, as illustrated in fig. 2A, 2B, and 6) and read their system information in order to ascertain which PLMN or PLMNs the cells belong to. Taking fig. 2A as an example, where n=n1=3, cells C1, C2 and C3 are the N1 strongest cells on carrier frequency f1 that meet the high quality criterion. From the system information of cells C1, C2 and C3, the UE can know that cells C1, C2 and C3 belong to plmn#1, plmn#2 and plmn#3, respectively. In some of the present embodiments, on each unlicensed carrier, the UE may search for up to N strongest cells and read their system information in order to ascertain to which PLMN or PLMNs the cells belong.

In some of the present embodiments, the value of N may be predefined (e.g., defined by 3GPP specifications), preconfigured to the UE (e.g., stored in the USIM and/or stored in the UICC), or configured by one or more cells (e.g., via system information and/or via dedicated signaling), making decisions based on the UE implementation.

In some of the present embodiments, the UE may search for N strongest cells supporting PLMN types (e.g., public, private, public, and private) of the UE and read their system information. For example, if the UE supports a public PLMN, the UE may search for N strongest cells supporting the public PLMN and read their system information. In this case, the largest N strongest cells searched support the PLMN type of the UE (e.g., public, private, public and private).

In some of the present embodiments, the UE may search for N strongest cells regardless of the PLMN type they support and read their system information. In this case, the N strongest cells searched may not support the PLMN type of the UE. In some of the present embodiments, if the UE cannot search for N strongest cells on the unlicensed carrier frequency, the UE may instead search for X strongest cells on the unlicensed carrier frequency, where X is a positive integer less than N, and read their system information. The value of X may be preconfigured or left for the UE to implement.

In some of the present embodiments, the search for PLMNs may be stopped/modified (e.g., changing the N or X value) upon request from the NAS entity of the UE. The UE may prioritize PLMN searches for the N strongest cells and/or the X strongest cells by using stored information (e.g., information of carrier frequencies) and optionally also information of cell parameters from previously received measurement control information elements.

In some of the present embodiments, the UE may measure channel occupancy of all carrier frequencies. The UE may select the carrier frequency with the lowest channel occupancy and read the system information of the cell on the selected carrier frequency.

If the UE reads one or more PLMN IDs in each of the N strongest cells, each found PLMN may be reported as one or more high quality PLMNs to the NAS entity of the UE. In some of the present embodiments, if the UE reads one or more PLMN IDs in each of the N strongest cells, each found PLMN (which each belongs to a PLMN type supported by the UE (e.g., public, private, or public and private)) may be reported as one or more high quality PLMNs to the NAS entity of the UE. In such cases, the one or more found PLMNs to report to the NAS entity of the UE may be considered AS one or more available PLMNs reported to the NAS entity of the UE by the AS entity of the UE.

In some of the present embodiments, if the measured metric value of a cell is greater than or equal to a threshold value (e.g., -110 dBm), a high quality criterion for finding the N strongest cells may be satisfied. The measured metric value may be at least one of an RSRP value, an RSRQ value, a received signal strength indication (Received Signal Strength Indicator, RSSI) value, a signal to Noise-plus-Noise Ratio (SINR) value, and a channel occupancy value. The threshold may be predefined, preconfigured or configured by the cell through system information (e.g., via SIB1 or other SI) or dedicated signaling (e.g., via RRC messages). For example, the measured RSPP value may be greater than or equal to a threshold value, e.g., -110dBm. If system information and dedicated signaling are adopted, the threshold may be stored by the UE and used in a later PLMN selection procedure. For example, the UE may use a stored threshold given by SI or dedicated signaling for PLMN selection. Whether a cell is "strong" may depend on the measured value of the cell. For example, if RSPP values are used as measurement values, the UE may form a list of cells with respect to unlicensed carrier frequencies according to the order of RSPP values of cells on unlicensed carrier frequencies. For example, the cell list may include cell IDs (or other identifying information of cells) that are ordered from highest measured metric value to lowest measured metric value according to the measured metric values of their corresponding cells. In some of the present embodiments, the UE may measure an unlicensed carrier frequency or a licensed carrier frequency for a time period (Tm). The value of Tm may be predefined, preconfigured, or dependent on the UE implementation. If Tm is not configured to the UE, then the default value of Tm may be adopted by the UE. In some of the present embodiments, tm may be dynamically configured to the UE by the cell via system information (e.g., SIB1 or other SI) or dedicated signaling (e.g., via RRC messages). In some of the present embodiments, the measured value may be obtained from measurements during the period Tm. In some of the present embodiments, the measured values may be obtained by averaging a set of measured values sampled over a period of time Tm.

In some of the present embodiments, if the N strongest cells satisfy the high quality criterion, the AS entity of the UE may report to the NAS entity of the UE identification information (e.g., one or more PLMN IDs, and/or one or more NIDs, one or more PLMN IDs, and/or one or more CAGs) of PLMNs found from the broadcasted system information of the N strongest cells, without reporting one or more measurement values. In some of the present embodiments, when the N strongest cells satisfy the high quality criterion, the AS entity of the UE may report to the NAS entity of the UE the identification information (e.g., one or more PLMN IDs, and/or one or more NIDs, one or more PLMN IDs, and/or one or more CAGs) of the PLMNs found from the system information broadcast by the N strongest cells and the measurement metrics of the N strongest cells. In some of the present embodiments, when the N strongest cells do not meet the high quality criterion but the UE has detected the identification information (e.g., one or more PLMN IDs, and/or one or more NIDs, one or more PLMN IDs, and/or one or more CAGs) of the PLMNs from the system information broadcast by the N strongest cells, the AS entity of the UE may report the detected identification information of the PLMNs and the measurement metrics of the N strongest cells to the NAS entity of the UE. In some of the present embodiments, the measured value of each PLMN found on the same N strongest cells may be the same. In some of the present embodiments, the measured value for each PLMN found on the N strongest cells that does not meet the high quality criterion may be the same.

In some of the present embodiments, if the number of cells satisfying the high quality criterion is greater than or equal to 1 but less than N, the AS entity of the UE may report the identification information of the PLMN found on the cells satisfying the high quality criterion to the NAS entity of the UE. In some of the present embodiments, if the number of cells satisfying the high quality criterion is greater than or equal to 1 but less than N, the AS entity of the UE may report to the NAS entity of the UE the identification information of PLMNs found on cells not satisfying the high quality criterion and the measured value of each PLMN found on cells not satisfying the high quality criterion. In some of the present embodiments, if the number of cells satisfying the high quality criterion is zero, the AS entity of the UE may report the identification information of PLMNs found on the N strongest cells and the corresponding measurement metrics of the N strongest cells. In some of the present embodiments, if the ranking of the measured values of a cell is in the top N but the UE cannot read any PLMN ID from this cell, the UE may not treat such cell as one of the N strongest cells. In some of the present embodiments, the UE may then store information of cells (e.g., relative cell IDs) that may be given lower priority to be selected as a suitable cell compared to other cells and consider the information for further cell (re) selection. The UE may remove information (e.g., relative cell ID) of the cell after the cell selection procedure, after the cell reselection procedure, or after a certain period of time.

In some of the present embodiments, the AS entity of the UE may select a PLMN AS a result of the PLMN selection procedure. This type of PLMN selection procedure may be referred to AS a procedure of PLMN selection by the UE AS.

In some of the present embodiments, during the procedure of PLMN selection by the UE AS, the NAS entity of the UE may provide the potential PLMN list to the AS entity of the UE. The potential PLMN list may include at least one PLMN-related ID. In some embodiments, the one or more PLMN-related IDs may be one or more PLMN IDs, one or more SNPN IDs, or one or more PNI-NPN IDs. The one or more SNPN IDs may include one or more PLMN IDs and/or one or more NIDs. The one or more PNI-NPN IDs may include one or more PLMN IDs and/or one or more CAG IDs.

The AS entity of the UE may select one or more PLMN related IDs from the potential PLMN list and report the one or more selected PLMN related IDs in the selected PLMN list to the NAS entity of the UE. In some of the present embodiments, the AS entity of the UE may inform the NAS entity of the UE of the ID related to the one or more selected PLMNs by reporting one or more indexes of one or more potential PLMN lists. In some of the present embodiments, if the AS entity of the UE cannot select any PLMN related IDs from the potential PLMN list, the AS entity of the UE may report a default value to the NAS entity of the UE to indicate the selected PLMN. In some of the present embodiments, the PLMN-related ID of the selected PLMN may be at the beginning (or end) of the selected PLMN list.

In some of the present embodiments, once the AS entity of the UE has selected a PLMN, the search for PLMNs may be stopped. In some of the present embodiments, once the UE's AS entity has found the N strongest cells, the search for PLMNs may be stopped. In some of the present embodiments, the PLMN IDs broadcast by the N strongest cells may not match the potential PLMN list. In some of the present embodiments, the one or more PLMN IDs broadcast by the N strongest cells may match the potential PLMN list, and the AS entity of the UE may select one or more PLMNs that match the potential PLMN list. In some of the present embodiments, once the AS entity of the UE has found all cells or the N strongest cells that meet the high quality criterion, the search for PLMNs may be stopped.

In some of the present embodiments, the PLMN related ID of the PLMN selected by the AS entity of the UE may be broadcast by one or more of the N strongest cells via SIB1 or other SI. In this case, the N strongest cells may meet the high quality criterion. In some of the present embodiments, the AS entity of the UE may select a PLMN whose PLMN related IDs are broadcast by most cells meeting high quality criteria. These cells may operate in intra-frequency (intra-frequency) or inter-frequency (inter-frequency). In some of the present embodiments, the AS entity of the UE may select a PLMN whose PLMN-related ID is broadcast by most cells for which the UE has been able to read the PLMN-related ID. In some of the present embodiments, the AS entity of the UE may select a PLMN whose PLMN related ID is broadcast by the cell having the strongest measured metric value among the cells broadcasting the potential PLMN list of the UE.

In some of the present embodiments, if the NAS entity of the UE verifies/approves the PLMN selected by the AS entity of the UE, the NAS entity of the UE may provide a positive indicator to the AS entity of the UE. After receiving the positive indicator, the AS entity of the UE may perform a cell selection procedure to select a suitable cell belonging to the selected PLMN to camp on. Conversely, if the NAS entity of the UE cannot verify (or reject) the selected PLMN, the NAS entity of the UE may provide a negative indicator to the AS entity of the UE. After receiving the negative indicator, the AS entity of the UE may trigger a PLMN selection procedure. In some of the present embodiments, after receiving the negative indicator, the AS entity of the UE may prohibit the reporting PLMN for a period of time to avoid re-selection thereof. In some of the present embodiments, after receiving the negative indicator, the AS entity of the UE may report another PLMN in the selected PLMN list to the NAS entity of the UE. If there are no other PLMNs in the selected PLMN list, the AS entity of the UE may trigger a PLMN selection procedure. In some of the present embodiments, if the NAS entity of the UE cannot verify (or reject) the selected PLMN, the NAS entity of the UE may independently select a PLMN from the selected PLMN list. In some of the present embodiments, if the NAS entity of the UE selects a PLMN, the NAS entity of the UE may indicate to the AS entity of the UE which PLMN is selected.

In some of the present embodiments, the AS entity of the UE may select a PLMN and report the selected PLMN list to the NAS entity of the UE. The selected PLMN list may include identification information for the selected PLMN (e.g., one or more PLMN-related IDs for one or more selected PLMNs). For example, the PLMN-related ID of the selected PLMN may be arranged by default in the first entry or the last entry of the selected PLMN list. In some of the present embodiments, an indicator may be used in the selected PLMN list to mark the selected PLMN. In some of the present embodiments, once the UE's AS entity confirms that the selected PLMN has been verified by the UE's NAS entity (e.g., the UE's AS entity reports the selected PLMN to the UE's NAS entity and then receives a positive indicator from the UE's NAS entity), the UE may perform a cell selection procedure to select a suitable cell belonging to the selected PLMN to camp on. In some of the present embodiments, the suitable cells may meet high quality criteria. In some of the present embodiments, if a cell in which the UE receives the PLMN ID of the selected PLMN does not meet the high quality criterion, the UE may perform a cell (re) selection procedure to find another cell as a suitable cell (e.g., the UE will not directly select such a cell as a suitable cell).

After PLMN selection, the UE may perform a cell selection procedure to ascertain the appropriate cells on the carrier frequency that belong to the selected PLMN. In some of the present embodiments, the UE may perform measurements for cell selection and reselection purposes. The NAS entity of the UE may control one or more RATs. For example, during a cell selection procedure, a NAS entity of a UE may request that an AS entity of the UE perform measurements on unlicensed spectrum (e.g., including one or more unlicensed carrier frequencies) of one or more unlicensed RATs (e.g., NR-U). The NAS entity of the UE may indicate to the AS entity of the UE one or more RATs associated with the selected PLMN (e.g., one or more equivalent PLMNs or registered PLMNs). In some of the present embodiments, the NAS entity of the UE may maintain at least one of a list of one or more forbidden registration areas and a list of one or more equivalent/registered PLMNs. In some of the present embodiments, the NAS entity of the UE may define the range of the registration-prohibited area by GPS coordinates. The UE may select a suitable cell based on rrc_idle or rrc_inactive state measurements and cell selection criteria. In some of the present embodiments, the UE may utilize rrc_connected state measurements for cell (re) selection.

In an unlicensed carrier frequency, the best cell found by the UE on the unlicensed carrier frequency may not belong to the selected/registered/equivalent PLMN, since multiple PLMNs may use the same carrier frequency without any coordination. In some of the present embodiments, if the best cell does not belong to the selected/registered/equivalent PLMN, the UE may select a non-best cell on an unlicensed carrier frequency as the suitable cell to camp on. In some of the present embodiments, the non-optimal cell may have better received radio signal quality than other cells belonging to the selected/registered/equivalent PLMN. Taking fig. 2B as an example, the best cell C1 does not belong to the selected plmn#2, so the UE may skip cell C1 and select the next best cell C2 (which belongs to the selected plmn#2) as the appropriate cell to camp on. Further, cell C2 may have better received radio signal quality than other cells belonging to the selected PLMN #2 (e.g., cell CK).

In some of the present embodiments, for initial cell selection, if the UE is instructed to use one or more unlicensed RATs, the UE may scan all Radio Frequency (RF) channels in an unlicensed band according to its ability to find a suitable cell. On each carrier frequency within the unlicensed spectrum, the UE may read the system information of the cell and search for the strongest cell belonging to the selected/registered/equivalent PLMN of the UE. That is, among all cells broadcasting identification information of the selected/registered/equivalent PLMN of the UE in each carrier frequency, the UE may find the strongest cell as a suitable cell. In contrast, among all cells in each carrier frequency, a cell (e.g., cell C1 illustrated in fig. 2B) that does not broadcast identification information of the selected/registered/equivalent PLMN may not be selected as a suitable cell even though the cell has better received radio signal quality than other cells.

In some of the present embodiments, the UE may be configured with a threshold. The threshold may be preconfigured or broadcast by the cell. In some of the present embodiments, the threshold may be a cell-specific threshold broadcast by each cell. Such a cell-specific threshold may be applied to the corresponding cell to determine whether the cell has good signal quality to be selected as a suitable cell. For example, on each carrier frequency, the UE may search for cells with measured metric values above a threshold. Among the cells searched, the UE may find a suitable cell. As illustrated in fig. 2B, each of cells C1, C2, and C3 on carrier frequency f1 may have a measured value above a threshold. Among the cells C1, C2, C3, the UE may consider the cell C2 as a suitable cell because the cell C2 belongs to the selected plmn#2.

In some of the present embodiments, the UE may need information of a carrier frequency, which the UE may receive from a measurement control information element of a camping/serving cell and/or from system information of a camping/serving/detected cell, for performing a cell (re) selection procedure. In some of the present embodiments, the UE may need information of cell parameters, which the UE may receive from measurement control information elements of the camped/serving cell and/or from system information of the camped/serving/detected cell for performing a cell (re) selection procedure. In some of the present embodiments, if a cell does not broadcast a threshold, the UE may treat the cell as a suitable cell at all times. For example, the UE may assume that the threshold of the cell is minus infinity. In some of the present embodiments, if the cell does not broadcast a threshold, the UE may use a default threshold to compare between the received signal quality and the threshold. In some of the present embodiments, when a cell prohibits all UEs, the threshold broadcasted by the cell may be set to positive infinity. In some of the present embodiments, when the UE prohibits a cell, the UE may set a threshold value of a corresponding cell to positive infinity.

In some of the present embodiments, on each carrier frequency, the UE may search for a cell that satisfies the following two conditions: (1) Such cells belong to a selected/registered/equivalent PLMN of the UE; and (2) the measured metric value of such cells is above a threshold value. Among the cells searched on each frequency, the UE may select the strongest cell (e.g., with the best metric value) as the appropriate cell. In some of the present embodiments, once the UE finds a cell satisfying the above two conditions, if the cell is not prohibited by the UE, the UE may directly select the cell as a suitable cell.

In some of the present embodiments, the UE may use the cell selection criterion S to find a suitable cell. In some of the present embodiments, the cell selection criterion S may be different between licensed spectrum and unlicensed spectrum. For example, for a cell selection procedure on licensed spectrum, the cell selection criterion S in normal coverage may be satisfied when:

srxlev >0 and square >0,

wherein:

Srxlev＝Q _rxlevmeas –(Q _rxlevmin +Q _{rxlevminoffset} )–P _compensation –Qoffset _temp and (2) and

Squal＝Q _qualmeas –(Q _qualmin +Q _{qualminoffset} )–Qoffset _temp

wherein:

/>

in some of the present embodiments, other criteria may be applicable to unlicensed spectrum operation. For example, the SINR value may be a measured metric value. The UE may compare the signal strength from the cell with the interference caused by other cells. In some of the present embodiments, the SINR value may be defined by a Synchronization Signal (SS) -SINR (SS-SINR) value. For example, the SS-SINR value may be defined as, but is not limited to, a linear average over a power distribution (in W) of resource elements carrying (secondary) SS divided by a linear average over noise and interference power distribution (in W) over resource elements carrying (secondary) SS within the same frequency bandwidth. In some of the present embodiments, one or more time resources for measuring SS-SINR values may be limited to SS/physical broadcast channel (Physical Broadcast Channel, PBCH) block measurement time configuration (SS/Physical Broadcast Channel Block Measurement Time Configuration, SMTC) window duration. The UE may receive SMTC for measuring the cell via dedicated signaling or system information from this or other cells.

In some of the present embodiments, the SINR value of the cell may be greater than or equal to a threshold (e.g., S _SINR >0，S _SINR ＝Q _SINR -Q _{SINR_th} +R _SINR )。S _SINR May be an S criterion associated with SINR values. Q (Q) _SINR May be a measured cell RX SINR value (dB). Q (Q) _{SINR_th} May be a threshold associated with the SINR value. R is R _SINR May be the remaining items (if necessary). Each item may be broadcast to the UE by the cell, unicast by the cell via dedicated signaling, or preconfigured to the UE (e.g., stored in the USIM and/or stored in the UICC). In the present practiceIn some of the embodiments, R _SINR May be zero. Q (Q) _{SINR_th} May be preconfigured or broadcast in a master information block (Master Information Block, MIB) or SIB1 from the cell. Q (Q) _{SINR_th} May be cell specific or unique to the system. For example, if Q _{SINR_th} Is cell-specific, it is applicable to broadcast Q _{SINR_th} A cell of values.

For a cell selection procedure in multi-beam operation, the average SINR among the beams of the cell may be considered. For example, the beam average SINR value of the cell may be greater than or equal to a threshold (e.g., S _{SINR_av} >0，S _{SINR_av} ＝Q _{SINR_av} -Q _{SINR_th_av} +R _{SINR_av} )。S _{SINR_av} May be an S criterion associated with the beam average SINR. Q (Q) _{SINR_av} May be the beam average SINR of the cell. Q (Q) _{SINR_th_av} May be a threshold associated with the beam average SINR. R is R _{SINR_av} May be the remaining items (if necessary). Each item may be broadcast to the UE by the cell, unicast by the cell via dedicated signaling, or preconfigured to the UE (e.g., stored in the USIM and/or stored in the UICC). In some of the present embodiments, R _{SINR_av} May be zero. Q (Q) _{SINR_th_av} May be cell specific or unique to the system. If Q _{SINR_th} Is cell-specific, it is applicable to broadcast Q _{SINR_th} A cell of values.

In some of the present embodiments, the UE may derive SINR values of the beams. Thus, for each beam, there may be a SINR value. There are many ways to define beam-specific SINR. For example, if there is a "B" beam, Q _{SINR_th_av} May be derived from the sum of all beam-specific SINR values divided by "B". In another example, if there is a "B" beam, Q _{SINR_th_av} Can be derived from the sum of all received signals of a beam divided by the sum of all interference and noise of all beams. The measurement quantity may be SS/PBCH blocks of a cell. Each SS/PBCH block of a cell may correspond to a beam. The value of "B" may be a positive integer.

In some of the present embodiments, a threshold (e.g., Q _{SINR_Beam_th} ) Can be used asAnd (5) configuration. Only SINR values are above a threshold (e.g., Q _{SINR_Beam_th} ) Can be used to derive a beam average SINR value. For example, if there is an SINR value above the threshold (e.g., Q _{SINR_Beam_th} ) "B1" beam of (C), Q _{SINR_th_av} May be derived from the sum of the B1 beam-specific SINR values divided by "B1". In some of the present embodiments, if there is a "B1" beam, Q _{SINR_th_av} Can be derived from the sum of all received signals of a beam divided by the sum of all interference and noise of all beams. If there is no beam-specific SINR value above the threshold (e.g., Q _{SINR_Beam_th} ) The highest SINR value among the beams may be used for the S criterion. For example, the highest SINR among the beams may be used as Q _{SINR_av} . In some of the present embodiments, if "B1" is higher than or equal to another value "B2", only the SINR values of the B2 beams may be used to derive the beam average SINR value. For example, the highest "B2" SINR value among the "B1" SINR values may be used. In another example, the lowest "B2" SINR values among the "B1" SINR values may be used. In yet another example, the "B2" SINR values may be randomly selected from the "B1" SINR values. In some of the present embodiments, the "B2" value may be preconfigured or broadcast by the cell. The "B2" value may be sent by the cell via dedicated signaling. On the other hand, "Q _{SINR_Beam_th} The "value" may be preconfigured to the UE or broadcast to the UE by the cell. "Q _{SINR_Beam_th} The "value" may be sent by the cell via dedicated signaling. The values of "B1" and "B2" may be one or more positive integers.

In some of the present embodiments, the carrier frequency bandwidth of the RAT over the unlicensed spectrum (e.g., NR-U) may be, but is not limited to, 20MHz. The carrier frequency of the RAT on the unlicensed spectrum may be a multiple of 20MHz if bandwidth is considered. For example, the unlicensed carrier frequency may have a channel bandwidth of 100 MHz. For another example, the 100MHz bandwidth may be divided into five different unlicensed carrier frequencies, with each unlicensed carrier frequency having a channel bandwidth of 20MHz.

In some of the present embodiments, the cell reselection procedure on unlicensed spectrum (e.g., NR-U) may take into account (reselection) priority and ranking. In some of the present embodiments, the absolute priority of the different NR frequencies, different NR-U frequencies, or inter-RAT frequencies may be provided to the UE in system information (e.g., SIB1, SIB2, SIB3, SIB4, SIB 5), in dedicated signaling (e.g., RRC (connection) release message with suspension configuration, RRC (connection) release message without suspension configuration), or by inheriting from another RAT during inter-RAT cell (re) selection. In some of the present embodiments, NR frequencies, NR-U frequencies, or inter-RAT frequencies may be listed without providing priority with respect to system information (e.g., for the frequencies, a field cellReselection priority may be missing). If priorities are provided in dedicated signaling (e.g., RRC (connection) release message with suspension configuration, RRC (connection) release message without suspension configuration), the UE may ignore all priorities provided in the system information.

In some of the present embodiments, the NR frequency and NR-U frequency can be inter-frequency if NR and NR-U are considered to be the same RAT. In some of the present embodiments, the NR frequency and NR-U frequency can be inter-RAT frequencies if the NR and NR-U are considered to be different RATs. In some of the present embodiments, different unlicensed carrier frequencies of the same RAT (e.g., NR-U) may be considered as inter-frequency.

In some of the present embodiments, the cell may broadcast priority information (e.g., inter-RAT frequency priority and/or inter-frequency priority). For example, priority information may be included in SIB1 and/or other SIs (e.g., SIB2, SIB3, SIB4, and SIB 5). The cell may inform the UE of the priority information via dedicated signaling (e.g., RRC release message). In some of the present embodiments, different RATs may have different priorities (e.g., RAT-specific priorities). In some of the present embodiments, different carrier frequencies may have different priorities, e.g., frequency-specific priorities. For example, for an E-UTRA RAT, the frequency priority information may include a carrier frequency of the E-UTRA, a cell reselection priority corresponding to the carrier frequency, and optionally a cell reselection sub-priority. For an NR RAT, the frequency priority information may include a carrier frequency of the NR, a cell reselection priority corresponding to the carrier frequency, and optionally a cell reselection sub-priority corresponding to the carrier frequency. For an NR-U RAT, the frequency priority information may include the carrier frequency of the NR-U, a cell reselection priority corresponding to the carrier frequency, and optionally a cell reselection sub-priority corresponding to the carrier frequency. In some of the present embodiments, the frequency priority information of the NR RAT may include a carrier frequency of the NR-U RAT, a cell reselection priority corresponding to the carrier frequency, and optionally a cell reselection sub-priority corresponding to the carrier frequency.

In some of the present embodiments, the UE may rank the serving cell and the non-serving cell (e.g., intra-frequency cell, inter-frequency cell, and inter-RAT cell) based on the measurement results. For RATs on unlicensed spectrum (e.g., NR-U), an intra-frequency cell may belong to the same PLMN as the serving cell, or to a different PLMN than the serving cell's PLMN. Similarly, for RATs on unlicensed spectrum (e.g., NR-U), an inter-frequency cell may belong to the same PLMN as that of the serving cell, or a different PLMN from that of the serving cell. In some of the present embodiments, the UE may rank the serving cell and non-serving cells (e.g., intra-frequency cells, inter-frequency cells, and inter-RAT cells) belonging to the same PLMN as the PLMN of the serving cell. In some of the present embodiments, the UE may rank the serving cell and non-serving cells (e.g., intra-frequency cells, inter-RAT cells) that may not belong to exactly the same PLMN as the PLMN of the serving cell.

In some of the present embodiments, the RAT on the unlicensed spectrum may be another RAT than the RAT on the licensed spectrum. For example, an NR-U with a PCell on an unlicensed spectrum may be a different RAT than an NR (which may be assumed to have a PCell on a licensed spectrum). For example, E-UTRA over licensed spectrum may be another RAT than NR-U operating over unlicensed spectrum. In some of the present embodiments, the different inter-RAT information may include E-UTRA specific information, NR specific information, and NR-U specific information.

In some of the present embodiments, when evaluating Srxlev of a non-serving cell for cell reselection purposesAnd square, the UE may use parameters provided by the serving cell. Some rules may be used by the UE to limit the required measurements. In some of the present embodiments, if the serving cell satisfies Srxlev>S _IntraSearchP And square>S _IntraSearchQ The UE may choose not to perform intra-frequency measurements. Otherwise, the UE may perform intra-frequency measurements. For example, in the case of RSPP, S _IntraSearchP May be an Srxlev threshold (in dB) of intra-frequency measurement. For example in terms of RSRQ, S _IntraSearchQ May be a square threshold (in dB) of intra-frequency measurements. In some of the present embodiments, if the serving cell satisfies S _SINR >S _{IntraSearchSINR} The UE may choose not to perform intra-frequency measurements. Otherwise, the UE may perform intra-frequency measurements. For example, in terms of SINR, S _{IntraSearchSINR} May be a threshold value (in dB) of intra-frequency measurement. In some of the present embodiments, if the serving cell satisfies S _{SINR_av} >S _{IntraSearchSINR_av} The UE may choose not to perform intra-frequency measurements. Otherwise, the UE may perform intra-frequency measurements. For example, in terms of average SINR, S _{IntraSearchSINR_av} May be a threshold value (in dB) of intra-frequency measurement. If multi-beam operation over unlicensed spectrum is used, S _{IntraSearchSINR_av} May be configured.

The inter-frequency cell reselection procedure on one or more unlicensed spectrum may require some rules. In some of the present embodiments, for an unlicensed inter-frequency having a higher reselection priority than that of the current frequency, the UE may perform measurement on the unlicensed inter-frequency. The current frequency may be an unlicensed carrier frequency or a licensed carrier frequency. The format of the cell reselection priority indicator may be corresponding to 2 ^N N bits of value. For example, a cell reselection priority indicator may mean the lowest priority when the value is 0. Further, a higher value of the cell reselection priority indicator may correspond to a higher cell reselection priority. In some of the present embodiments, a cell reselection sub-priority value may be added to a value of a cell reselection priority indicator corresponding to a frequency or RAT. That is, cell reselection sub-priority value and cell reselectionThe value of the priority indicator may constitute an absolute priority value of the RAT of interest or an absolute priority value of the carrier frequency of interest of the corresponding RAT. In some of the present embodiments, if the dedicated signaling (e.g., RRC (connection) release message, RRC release message with suspension configuration, RRC release message without suspension configuration) does not include a cell reselection priority indicator, the UE may apply the cell reselection priority indicator broadcasted with system information. In some of the present embodiments, if the system information does not include a cell reselection priority indicator, the UE may apply the stored cell reselection priority indicator. In some of the present embodiments, if the dedicated signaling and system information does not include a cell reselection priority indicator of the corresponding RAT/frequency and the UE does not store any cell reselection priority indicator of the corresponding RAT/frequency, the UE may apply a default value as the cell reselection priority indicator of the corresponding RAT/frequency. In some of the present embodiments, the default value may be zero, which means that the corresponding RAT/frequency may have the lowest priority. In some of the present embodiments, if the dedicated signaling and system information does not include a cell reselection priority indicator for the corresponding RAT/frequency and the UE does not store any cell reselection priority indicator for the corresponding RAT/frequency, the UE may consider the cell on the corresponding RAT/frequency as barred during the cell reselection procedure. For inter-frequency measurements, at least one of SINR values, RSSI values, and channel occupancy values may be used as a measurement metric. For example, the UE may perform measurements on cells in different frequencies based on SINR values, average SINR values, RSSI values, or channel occupancy values. For example, the UE may perform measurements on frequency based on RSSI values or channel occupancy values. In some of the present embodiments, if the measurement result (e.g., RSSI value or channel occupancy value) of such carrier frequency is worse than the measurement result of another frequency with lower (reselection) priority, the UE may decrease the priority of the carrier frequency to be selected in the cell reselection procedure.

In some of the present embodiments, for unlicensed inter-frequencies with reselection priorities equal to or lower than the reselection priority of the current frequency, if the serving cell satisfies Srxlev>S _{nonIntraSearchP} And square>S _{nonIntraSearchQ} The UE may decide not to perform measurements on unlicensed inter-frequencies. In some of the present embodiments, if the serving cell satisfies Srxlev>S _{nonIntraSearchSINR} The UE may decide not to perform measurements on unlicensed inter-frequencies (reselection priorities equal to or lower than the reselection priorities of the current frequency). For example, in terms of SINR, S _{nonIntraSearchSINR} The threshold (in dB) of the unlicensed inter-frequency measurement may be used. In some of the present embodiments, if the serving cell satisfies Srxlev>S _{nonIntraSearchSINR_av} The UE may decide not to perform measurements on unlicensed inter-frequencies (with reselection priorities equal to or lower than the reselection priorities of the current frequency). For example, in terms of average SINR, S _{nonIntraSearchSINR_av} The threshold (in dB) of the unlicensed inter-frequency measurement may be used. If multi-beam operation over unlicensed spectrum is used, S _{nonIntraSearchSINR_av} May be configured. In some of the present embodiments, the UE may perform unlicensed inter-frequency measurements if the condition is not satisfied.

In some of the present embodiments, if a measurement metric value (e.g., RSSI value or channel occupancy value) of a current frequency is above a threshold value, the UE may not perform measurements on unlicensed frequencies, regardless of priority among the unlicensed frequencies. The threshold may be configured by system information or dedicated signaling.

In some of the present embodiments, the UE (e.g., in rrc_connected state) may report measurement results (e.g., RSSI values or channel occupancy values) of different frequencies (e.g., in one or more unlicensed spectrum or one or more licensed spectrum) to the serving cell via dedicated signaling (e.g., measurement report message). Upon receiving the measurement results, the serving cell may adjust the (re-) priority of the different frequencies. Thus, the cell may send updated (re-) priorities of different frequencies to the UE with system information (e.g., with SIB1, SIB2, SIB3, SIB4, or SIB 5) or with dedicated signaling (e.g., with RRC (connection) release message, with RRC release message with suspension configuration, with RRC release message without suspension configuration). Upon acquiring the updated (reselection) priority, the UE may replace the stored value of the (reselection) priority with the updated (reselection) priority for cell reselection.

Some rules may be required for frequency cell reselection between different RATs between one or more unlicensed spectrum and one or more licensed spectrum. In some of the present embodiments, if frequencies between different RATs are unlicensed, each unlicensed carrier frequency may correspond to a reselection priority. In some of the present embodiments, if frequencies between different RATs are unlicensed, all unlicensed carrier frequencies may correspond to reselection priorities.

In some of the present embodiments, if a frequency between unlicensed different RATs (e.g., NR-U frequency) has a reselection priority that is higher than a reselection priority of a current licensed carrier frequency (e.g., NR frequency or E-UTRA frequency), the UE may perform measurements on the unlicensed inter-RAT frequency. In some of the present embodiments, if at least one licensed inter-RAT frequency (e.g., NR frequency or E-UTRA frequency) has a reselection priority that is higher than a reselection priority of a current licensed carrier frequency (e.g., NR frequency or E-UTRA frequency), the UE may not perform measurements on frequencies between unlicensed different RATs.

In some of the present embodiments, if a frequency (e.g., an NR frequency or an E-UTRA frequency) between licensed different RATs has a reselection priority that is higher than a reselection priority of a current unlicensed carrier frequency (e.g., an NR-U frequency), the UE may perform measurement of an licensed inter-RAT frequency having a higher reselection priority.

In some of the present embodiments, if the measurement metric value (e.g., SINR value, RSSI value, or channel occupancy value) of the current unlicensed carrier frequency is below a threshold, the UE may perform measurements on frequencies (e.g., NR frequencies or E-UTRA frequencies) between licensed different RATs. In some of the present embodiments, the threshold value of the corresponding measured metric value may be configured from the cell to the UE in system information or with dedicated signaling.

In some of the present embodiments, for frequencies between unlicensed different RATs with reselection priorities equal to or lower than the reselection priority of the current licensed carrier frequency, if the serving cell satisfies Srxlev>S _{nonIntraSearchP} And square>S _{nonIntraSearchQ} The UE may choose not to perform measurements on frequencies between unlicensed RATs. For example, in the case of RSRP, S _{nonIntraSearchP} May be a threshold (in dB) for unlicensed inter-RAT frequency measurements. For example in terms of RSRQ, S _{nonIntraSearchQ} May be a threshold (in dB) for unlicensed inter-RAT frequency measurements.

In some of the present embodiments, for an licensed inter-RAT frequency having a reselection priority equal to or lower than the reselection priority of the current unlicensed carrier frequency, if the serving cell satisfies the condition Srxlev>S _{nonIntraSearchP} And square>S _{nonIntraSearchQ} The UE may choose not to perform measurements on the licensed inter-RAT frequency. In some of the present embodiments, for an licensed inter-RAT frequency having a reselection priority equal to or lower than the reselection priority of the current unlicensed carrier frequency, if the serving cell satisfies the condition Srxlev>S _{nonIntraSearchSINR} The UE may choose not to perform measurements on the licensed inter-RAT frequency. For example, in terms of SINR, S _{nonIntraSearchSINR} May be a threshold (in dB) that grants inter-RAT frequency measurements. In some of the present embodiments, for an licensed inter-RAT frequency having a reselection priority equal to or lower than the reselection priority of the current unlicensed carrier frequency, if the serving cell satisfies the condition Srxlev >S _{nonIntraSearchSINR_av} The UE may choose not to perform measurements on the licensed inter-RAT frequency. For example, in terms of average SINR, S _{nonIntraSearchSINR_av} May be a threshold (in dB) that grants inter-RAT frequency measurements. If multi-beam operation over one or more unlicensed spectrum is used, S _{nonIntraSearchSINR_av} May be configured. In some of the present embodiments, if the above-mentioned condition is not satisfied, the UE may perform measurement of the licensed inter-RAT frequency.

In some of the present embodiments, if the highest ranked cell (or the best cell or strongest cell) on the unlicensed carrier frequency (e.g., the highest ranked cell is an unlicensed intra-frequency cell or an unlicensed inter-frequency cell) is not suitable to camp on because the highest ranked cell is part of a "list of 5G systems (5 gs) Tracking Areas (TAs) for roaming" or belongs to a PLMN that is not indicated as equivalent to a registered PLMN, the highest ranked cell is barred, and the UE may consider the highest ranked cell as an unsuitable cell to camp on for a maximum period of time T (e.g., 300) seconds. In this case, the UE may consider the other cells as candidate cells on the same unlicensed carrier frequency for the cell reselection procedure.

Cells on unlicensed carrier frequencies may be ranked based on their corresponding measured value or other absolute priority reselection rule. For example, the highest ranked cell may be the cell with the best received radio signal quality among the cells on the same carrier frequency. It should be noted that the "highest ranking cell", "best cell" and "strongest cell" may be interchangeable terms in some of the present embodiments.

In some of the present embodiments, the T value of the licensed intra-frequency cell case or the licensed inter-frequency cell case may be independent of the unlicensed intra-frequency cell case or the unlicensed inter-frequency cell case. The T values may be configured or predefined separately for different situations, and the T values may be different. In some of the present embodiments, the T value of the licensed intra-frequency cell case or the licensed inter-frequency cell case may be the same as the unlicensed intra-frequency cell case or the unlicensed inter-frequency cell case. In some of the present embodiments, the T values of different cases may be configured or predefined together.

In some of the present embodiments, if the highest ranked cell on an unlicensed carrier frequency is an unsuitable cell to camp on (e.g., the UE determines that the highest ranked cell is unsuitable to camp on), then when at least one cell on the other frequency is ranked by the UE and has a ranking value above the ranking threshold, the UE may not consider the cell on the same unlicensed carrier frequency as a candidate suitable cell for reselection for a maximum period of time T (e.g., 300) seconds. The ranking threshold may be preconfigured, broadcast by the serving cell (e.g., in SIB2, SIB3, SIB4, or SIB 5), or sent via RRC dedicated signaling (e.g., in an RRC (connection) release message, in an RRC release message with a suspension configuration, in an RRC release message without a suspension configuration).

In some of the present embodiments, if the highest ranked cell on an unlicensed carrier frequency is not suitable for camping on, then the UE may consider a cell on the same unlicensed carrier frequency as an unsuitable cell for a maximum period of time T seconds when at least one cell on the other frequency satisfies the cell selection criterion S.

In some of the present embodiments, if the highest ranked cell on an unlicensed carrier frequency is determined to be an unsuitable cell, the UE may further consider a cell on the same unlicensed carrier frequency as the unsuitable cell for a maximum period of time T (e.g., 300) seconds when the measured value (e.g., RSPP value, RSRQ value, or SINR value) of at least one cell on the other frequency is above a threshold. The threshold may be preconfigured, broadcast by the serving cell (e.g., in SIB2, SIB3, SIB4, SIB 5), or sent via RRC dedicated signaling (e.g., in an RRC (connection) release message, in an RRC release message with a suspension configuration, in an RRC release message without a suspension configuration).

In some of the present embodiments, the UE may be redirected to an unlicensed carrier frequency (e.g., to utilize an unlicensed RAT such as NR-U) under control of an licensed RAT (e.g., NR). Any restriction on unlicensed carrier frequencies operated by timer T may be removed if the UE is redirected to the unlicensed carrier frequencies under control of the licensed RAT. The restrictions may include any constraint that allows the UE to perform a cell (re) selection procedure on the unlicensed carrier frequency. For example, the UE may remove the restriction on the unlicensed carrier frequency by stopping the timer T. Thus, the UE may perform measurements on the unlicensed carrier frequency.

In some of the present embodiments, the UE may be redirected to an licensed carrier frequency (e.g., NR) under control of an unlicensed RAT (e.g., NR-U). Any restriction on the licensed carrier frequency operated by the timer T may be removed if the UE is redirected to the licensed carrier frequency under the control of an unlicensed RAT (e.g., NR-U). The restrictions may include any constraint that allows the UE to perform a cell (re) selection procedure on the licensed carrier frequency. For example, the UE may remove the restriction on the licensed carrier frequency by stopping the timer T. Thus, the UE may perform measurements on the licensed carrier frequency.

In some of the present embodiments, if an indication (e.g., threservinglowsinr) is broadcast with system information (e.g., threservinglowsinr) and more than Tr (e.g., 1) seconds have elapsed since the UE camps on the current serving cell, the UE may perform a cell reselection procedure to select a cell on a higher priority frequency than the serving frequency (e.g., a new suitable cell to camp on). Cells on higher priority RATs, licensed carrier frequencies or unlicensed carrier frequencies may satisfy: at time intervals (e.g., treselection _RAT ) During which the SINR value of the cell is above a threshold (e.g., thresh _X,HighSINR ). Otherwise, if the time interval (e.g., treselection _RAT ) During which the cell satisfies Srxlev>Thresh _X,HighP And more than 1 second has elapsed since the UE camps on the current serving cell, cell reselection may be performed as a cell on a higher priority frequency (e.g., intra-frequency or inter-frequency) than the serving frequency.

In some of the present embodiments, the frequency channel (which may correspond to a higher priority RAT, licensed carrier frequency, or unlicensed carrier frequency) of the selected cell (e.g., a new suitable cell during a cell reselection procedure) may satisfy: at time intervals (e.g., treselection _RAT ) The RSSI value of the frequency during the period is higher than a threshold (e.g., thresh _X,HighRSSI ). Otherwise, if the time interval (e.g., treselection _RAT ) During which the cell satisfies Srxlev>Thresh _X,HighP And more than 1 second has elapsed since the UE camps on the current serving cell, cell reselection may be performed as a cell on a higher priority frequency (e.g., intra-frequency or inter-frequency) than the serving frequency.

In some of the present embodiments, if an indication (e.g., threservinglowco) is broadcast with system information and more than Tr (e.g., 1) seconds have elapsed since the UE camps on the current serving cell, the UE may perform cell reselection as a cell on a higher priority frequency than the serving frequency. Higher priority R The frequency channels of the cells on the AT, licensed carrier frequency, or unlicensed carrier frequency may satisfy: at time intervals (e.g., treselection _RAT ) During which the channel occupancy value of the frequency is above a threshold (e.g. Thresh _X,HighCO ). Otherwise, if the time interval (e.g., treselection _RAT ) During which the cell satisfies Srxlev>Thresh _X,HighP And more than 1 second has elapsed since the UE camps on the current serving cell, cell reselection may be performed as a cell on a higher priority frequency (e.g., intra-frequency or inter-frequency) than the serving frequency.

In some of the present embodiments, if there is no specific indicator (e.g., thresServingLowSINR, thresServingLowRSSI, thresServingLowCO) broadcast with system information and more than Tr (e.g., 1) seconds have elapsed since the UE camps on the current serving cell, the UE may perform cell reselection as a cell on a higher priority frequency than the serving frequency. Based on the time interval (e.g., treselection _RAT ) During which RSPP (e.g., srxlev) is above a threshold (e.g., thresh _X,HighP ) The selected cell (e.g., the new suitable cell to camp on) may satisfy the cell selection RX level value.

In some of the present embodiments, the above-mentioned mechanism may be applied to a cell reselection procedure to change an original suitable cell of a UE from a cell in an licensed carrier frequency to a cell in an unlicensed carrier frequency, or from a cell in an unlicensed carrier frequency to a cell in an licensed carrier frequency, or from a cell in an unlicensed carrier frequency to a cell in an unlicensed carrier frequency, or from a cell in an licensed carrier frequency to a cell in an licensed carrier frequency.

In some of the present embodiments, if the UE camping on the cell in the source frequency reselects as the cell in the target frequency, the UE may start a timer based on the timer value. The UE may not measure and/or reselect cells in the source frequency until the timer expires. The UE may be configured with a timer value by a cell on the source frequency via system information (e.g., SIB1, other SI (e.g., SIB2 or SIB 3)) or dedicated signaling (e.g., RRC (connection) release message, suspension configuration in RRC release message, RRC release message with suspension configuration, RRC release message without suspension configuration). In some of the present embodiments, the timer value may be preconfigured or predefined. In some of the present embodiments, if the UE cannot reselect any cell in other frequencies, the UE may stop the timer. In other words, the UE may de-prioritize the source frequency to the lowest priority among all available frequencies (e.g., when the timer is running). In some of the present embodiments, if the UE camping on the target cell reselects to another target cell in the third frequency, the UE may stop the timer for the source frequency. Further, the UE may start a timer for the target frequency.

In some of the present embodiments, the UE may rank all cells within or between unlicensed frequencies that meet the cell selection criteria S. The UE may be based on cell ranking criteria R of the serving cell _s And cell ranking criteria R for neighboring cells _n The cells are ranked. In some of the present embodiments, the cell ranking criteria R of unlicensed serving cells _s And cell ranking criteria R for unlicensed neighbor cells (e.g., in unlicensed frequencies or in equal priority unlicensed inter-frequencies) _n Can be represented by R _s ＝Q _meas,s +Q _rmd,s And R is _n ＝Q _meas,n +Q _rmd,n Definition, wherein Q _meas,s May be a measurement metric value (e.g., RSRP value, RSRQ value, or SINR value) used in a cell reselection procedure, Q _rmd,s May be an adjustment term (e.g., hysteresis value), Q _meas,n May be a measurement metric value used in a cell reselection procedure, and Q _rmd,n May be an adjustment term (e.g., the offset value depends on an unauthorized intra-frequency or inter-frequency. R _s And R is R _n The comparison between may be based on the same measurement metric. In some of the present embodiments, the UE may receive Q from the serving cell via system information (e.g., SIB2, SIB3, SIB4, SIB5, or others) or via dedicated signaling (e.g., RRC (connection) release message, RRC release message with suspension configuration, RRC release message without suspension configuration) _rmd,s And Q _rmd,n Is a value of (2).

In some of the present embodiments, the UE may rank the (unlicensed) cells according to an R criterion and calculate an R value (e.g., R using an average measurement metric result (e.g., average RSRP/RSRQ/SINR value) of the corresponding cells _s And R is _n )。

In some of the present embodiments, the UE may re-rank the cells based on the registered PLMN or equivalent PLMN of the UE. The re-ranked cell ranking list may include all cells belonging to the same PLMN. For example, the UE may re-rank the cells by removing cells from the original cell ranking list that do not belong to the registered PLMN or equivalent PLMN. In this case, the original cell ranking list may include cells belonging to different PLMNs.

In some of the present embodiments, the UE may rank the cells based on a signal strength related measurement (e.g., RSRP, RSRQ, SINR). Cells belonging to different PLMNs on the same carrier frequency may be ranked together, which may refer to an "original cell ranking list". If the rename rule is applied, the rename cell rank list may include all cells belonging to the registered PLMN of the UE or an equivalent PLMN. In some of the present embodiments, the UE may perform a cell reselection procedure based on the original cell ranking list. In some of the present embodiments, the UE may perform a cell reselection procedure based on the re-ranked cell ranking list. In some of the present embodiments, the UE may perform an intra-frequency cell reselection procedure and/or an inter-frequency cell reselection procedure using the re-named cell ranking list. For example, the UE may reselect to a highest ranking cell among the cells listed in the ranked list of renamed cells on one or more licensed spectrums. For another example, the UE may reselect to a highest ranked cell of the cells listed in the ranked list of renamed cells on one or more unlicensed spectrum. For example, the UE may reselect to a highest ranked cell among cells listed in a ranked list of renamed cells that include one or more licensed spectrums and one or more unlicensed spectrums and that belong to cells of the same PLMN. In some of the present embodiments, if the cell ranking list on one or more licensed spectrums includes cells belonging to the same PLMN, the cell ranking list on one or more licensed spectrums may be regarded as a renamed cell ranking list.

In some of the present embodiments, if the UE has at least two original cell rows

List of names, wherein each list corresponds to one unlicensed carrier frequency, the UE may select as a suitable cell a cell satisfying the following two conditions: (1) the cell belongs to the selected/registered/equivalent PLMN; and (2) the cell is the highest ranked cell of the cells listed in the at least two original cell ranking lists. Furthermore, the selected cell may not be barred.

In some of the present embodiments, if an indication (e.g., rangeToBestCell) is not configured, the UE may perform a cell reselection procedure to select a new suitable cell ranked as the best cell. The best cells may be listed in the original cell rank list or the renamed cell rank list. In some of the present embodiments, if the best cell (or highest ranked cell) is found to be a non-suitable cell (e.g., not belonging to the registered PLMN or equivalent PLMN of the UE, not meeting the cell selection criterion S), the UE may select the next best cell (or next highest ranked cell) as the new suitable cell. The next best cell (or next highest ranked cell) is ranked lower than the best cell (or highest ranked cell).

In some of the present embodiments, if the UE finds that the selected cell is an unsuitable cell (e.g., not belonging to the registered PLMN or equivalent PLMN of the UE), the UE may select the next cell of the lower rank of the previously selected unsuitable cell. In some of the present embodiments, if the best cell is found to be an unsuitable cell (e.g., not belonging to the registered PLMN or equivalent PLMN of the UE, not meeting the cell selection criterion S), the UE may remove the cell belonging to the same PLMN as the best cell in the original cell ranking list.

In some of the present embodiments, if an indication (e.g., rangeToBestCell) is configured, the UE may perform a cell reselection procedure to select a new suitable cell. The new suitable cell is the cell of the plurality of cells having the most number of beams above the threshold (e.g., SINR-valued threshold, RSPP-valued threshold, or RSRQ-valued threshold), where the R-value of the plurality of cells is within the R-value indication (e.g., rangetbestcell) of the cell ranked as the best cell. For example, if the UE calculates the R value of the cell based on the (average) SINR value, the UE may count the number of beams above a threshold value of the SINR value of the cell. In some of the present embodiments, if there are a plurality of such cells, the UE may perform a cell reselection procedure to select a highest ranked cell among the plurality of such cells.

In some of the present embodiments, if the indication (e.g., rangeToBestCell) is configured, the UE may perform a cell reselection procedure to select a new suitable cell that belongs to the registered PLMN (or equivalent PLMN) of the UE and has the highest beam number above a threshold (e.g., SINR-valued threshold, RSPP-valued threshold, or RSRQ-valued threshold) among cells within the indication (e.g., rangeToBestCell) of the R value of the cell ranked as the best cell. In some of the present embodiments, the best cells may be listed in a re-named cell list. In some of the present embodiments, the best cell may or may not belong to the registered PLMN (or equivalent PLMN) of the UE. For example, if the UE calculates the R value of the cell based on the (average) SINR value, the UE may count the number of beams above a threshold value of the SINR value of the cell. In some of the present embodiments, if there are a plurality of such cells, the UE may perform a cell reselection procedure to select a highest ranked cell among the plurality of such cells.

In some of the present embodiments, the cell may broadcast a channel occupancy value or RSSI value based on the measurement of the cell on the unlicensed carrier frequency. If the broadcast channel occupancy value of a cell is above a threshold, the UE may not (re) select such a cell as the appropriate cell to camp on. Similarly, if the broadcast RSSI value of a cell is below a threshold, the UE may not (re) select such a cell as the appropriate cell. In some of the present embodiments, if the broadcast channel occupancy value of the cell is above a threshold, the UE may perform a different inter-frequency cell reselection procedure or a different inter-RAT cell reselection procedure to search for a new suitable cell in other frequencies.

In some of the present embodiments, if the broadcast RSSI value of the cell is below a threshold, the UE may perform a different inter-frequency cell reselection procedure or a different inter-RAT cell reselection procedure to search for a new suitable cell in other frequencies. If the UE receives multiple RSSI values from the cell, the UE may compare the average of the RSSI values to a threshold. In some of the present embodiments, the threshold may be broadcast to the UE or may be sent to the UE via dedicated signaling. In some of the present embodiments, the threshold may be a predefined value (e.g., determined based on a UE category, a UE target service type, or other UE characteristics). In some of the present embodiments, the UE may adjust the ranking of the cells based on the broadcast channel occupancy value or RSSI value of the cells.

In some of the present embodiments, the dedicated signaling referred to may refer to (but is not limited to) one or more RRC messages. The cell may transmit dedicated signaling to the UE, wherein the dedicated signaling may be an RRC (connection) setup message, an RRC (connection) reconfiguration message, an RRC connection reconfiguration message including mobility control information, an RRC connection reconfiguration message without mobility control information inside, an RRC reconfiguration message including synchronous configuration, an RRC reconfiguration message without synchronous configuration inside, an RRC (connection) resume message, an RRC (connection) reestablishment message, an RRC (connection) reject message, an RRC (connection) release message, an RRC release message including suspension configuration inside, an RRC release message without suspension configuration inside, and a UE capability query message, etc. The UE may transmit dedicated signaling to the cell, wherein the dedicated signaling may be an RRC (connection) setup request message, an RRC (connection) setup complete message, an RRC (connection) reconfiguration complete message, an RRC (connection) restoration request message, an RRC (connection) restoration complete message, an RRC (connection) reestablishment request message, an RRC (connection) reestablishment complete message, an RRC system information request message, a UE assistance information message, a UE capability information message, and the like.

The rrc_idle/rrc_inactive UE may camp on a cell, which may be referred to as a "camped cell". The rrc_connected UE may be served by a serving cell. When the UE enters rrc_idle/rrc_inactive, the serving cell may be a cell where the UE camps. When the UE enters rrc_connected, the camping cell may be the serving cell of the UE. If the UE can measure the radio signal strength from a cell, such a cell may be a detected cell for the UE.

Fig. 8 is a block diagram illustrating a node for wireless communication in accordance with various aspects of the disclosure. As shown in fig. 8, node 800 may include a transceiver 820, a processor 828, a memory 834, one or more presentation components 838, and at least one antenna 836. Node 800 may also include an RF spectrum band module, a BS communication module, a network communication module, and a system communication management module, input/output (I/O) ports, I/O components, and a power source (not explicitly shown in fig. 8). Each of these components may communicate with each other directly or indirectly through one or more buses 840. In one embodiment, node 800 may be a UE, BS, or any other device that communicates wirelessly that performs the various functions described herein, e.g., with reference to fig. 1-7.

A transceiver 820 having a transmitter 822 (e.g., transmission/reception) circuit and a receiver 824 (e.g., reception/reception circuitry) circuit) may be configured to transmit and/or receive time and/or frequency resource partition information. In some of the present embodiments, transceiver 820 may be configured to transmit in different types of subframes and slots, including but not limited to usable, unusable, and flexibly usable subframe and slot formats. Transceiver 820 may be configured to receive data and control channels.

Node 800 may include a variety of computer-readable media. Computer readable media can be any available media that can be accessed by node 800 and includes both volatile (and nonvolatile) media and removable (and non-removable) media. By way of example, and not limitation, computer readable media may comprise computer storage media and communication media. Computer storage media may include volatile (and/or nonvolatile) and removable (and/or non-removable) media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules, or data.

Computer storage media may include RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices. Computer storage media does not include propagated data signals. Communication media may typically be embodied by computer readable instructions, data structures, program modules, or other data in a modulated data signal, such as a carrier wave or other transport mechanism, and includes any information delivery media. The term "modulated data signal" may mean a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media may include wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared and other wireless media. Combinations of any of the above should also be included within the scope of computer readable media.

Memory 834 may include computer storage media in the form of volatile and/or nonvolatile memory. The memory 834 may be removable, non-removable or a combination thereof. Exemplary memory includes solid state memory, hard drives, optical drives, and the like. As illustrated in fig. 8, the memory 834 may store computer readable, computer executable instructions 832 (e.g., software code) that, when executed, are configured to cause the processor 828 to perform various functions described herein, for example, with reference to fig. 1-7. Alternatively, the instructions 832 may not be directly executed by the processor 828, but rather be configured to cause the node 800 (e.g., when compiled and executed) to perform the various functions described herein.

The processor 828 (e.g., with processing circuitry) may include intelligent hardware devices, such as a central processing unit (Central Processing Unit, CPU), a microcontroller, an ASIC, or the like. Processor 828 may include memory. Processor 828 may process data 830 and instructions 832 received from memory 834 as well as information passing through transceiver 820, a baseband communication module, and/or a network communication module. Processor 828 may also process information to be sent to transceiver 820 for transmission to a network communication module via antenna 836 for transmission to a core network.

One or more presentation components 838 can present data indications to a person or other device. Examples of presentation components 838 may include a display device, speakers, a printing component, a vibrating component, and so forth.

From the foregoing description, it will be evident that various techniques may be used to implement the concepts described in this disclosure without departing from the scope of those concepts. Furthermore, while the present concepts have been described with reference to certain embodiments, one of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of those concepts. The described embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. It should also be understood that the application is not limited to the particular embodiments described above, but is capable of many rearrangements, modifications, and substitutions without departing from the scope of the disclosure.

Claims (16)

1. A user equipment, UE, comprising:

one or more non-transitory computer-readable media having computer-executable instructions embodied thereon; and

at least one processor coupled to the one or more non-transitory computer-readable media and configured to execute the computer-executable instructions to:

reading system information of a plurality of cells on a first carrier frequency to obtain identification information of a plurality of public land mobile networks PLMNs, wherein the first carrier frequency is an unlicensed carrier frequency;

reporting, by an Access Stratum (AS) entity of the UE, the identification information of the plurality of PLMNs to a non-access stratum (NAS) entity of the UE;

selecting, by the NAS entity of the UE, one of the plurality of PLMNs as the selected PLMN;

during a cell selection procedure, searching the plurality of cells on the first carrier frequency;

selecting a suitable cell belonging to the selected PLMN from the plurality of cells on the first carrier frequency as a result of the cell selection procedure; and

a cell reselection procedure is performed to select a new suitable cell, the cell reselection procedure comprising:

Determining whether a highest ranked cell on the first carrier frequency belongs to one of the selected PLMN and a PLMN indicated as being equivalent to a registered PLMN of the UE;

selecting the highest ranked cell as the new suitable cell when the highest ranked cell belongs to one of the selected PLMN and the PLMN indicated as being equivalent to the registered PLMN of the UE; and

when the highest ranked cell on the first carrier frequency is not selected as the new suitable cell,

prohibiting the highest ranking cell from being selected as the new suitable cell for a first period of time; and

iteratively performing a process on the first carrier frequency until the new suitable cell is found on the first carrier frequency or a certain number of cells on the first carrier frequency are determined to be unsuitable cells, the process comprising:

determining whether a next highest ranking cell on the first carrier frequency belongs to one of the selected PLMN and the PLMN indicated as being equivalent to the registered PLMN of the UE;

selecting the next highest ranked cell as the new suitable cell when the next highest ranked cell belongs to one of the selected PLMN and the PLMN indicated as being equivalent to the registered PLMN of the UE; and

And when the next highest ranking cell is not selected as the new suitable cell, determining that the next highest ranking cell is a non-suitable cell.

2. The UE of claim 1, wherein the at least one processor is further configured to execute the computer-executable instructions to:

when the total number of unsuitable cells on the first carrier frequency reaches the certain number, the new suitable cell is searched on a second carrier frequency.

3. The UE of claim 2, wherein the at least one processor is further configured to execute the computer-executable instructions to:

determining whether another highest ranked cell on the second carrier frequency belongs to one of the selected PLMN and the PLMN indicated as being equivalent to the registered PLMN of the UE;

selecting the other highest ranked cell as the new suitable cell when the other highest ranked cell belongs to one of the selected PLMN and the PLMN indicated as being equivalent to the registered PLMN of the UE;

prohibiting the other highest ranked cell on the second carrier frequency from being selected as the new suitable cell for a second period of time when the other highest ranked cell is not selected as the new suitable cell;

Wherein the length of the second time period is independent of the length of the first time period.

4. The UE of claim 1, wherein the at least one processor is further configured to execute the computer-executable instructions to:

when the total number of unsuitable cells on the first carrier frequency reaches the particular number, the first carrier frequency is de-prioritized in a set of carrier frequencies for a second period of time for the cell reselection procedure.

5. The UE of claim 1, wherein the highest ranked cell and the next highest ranked cell on the first carrier frequency are ranked according to received radio signal quality, and the next highest ranked cell has a worse received radio signal quality than the highest ranked cell.

6. The UE of claim 1, wherein the highest ranked cell and the next highest ranked cell belong to two different PLMNs of the plurality of PLMNs.

7. The UE of claim 1, wherein the system information includes PLMN type information indicating at least one PLMN type associated with the plurality of cells.

8. The UE of claim 1, wherein the at least one processor is further configured to execute the computer-executable instructions to:

providing, by the NAS entity of the UE, a message to the AS entity of the UE, the message indicating which of one or more PLMN types the UE supports;

wherein the one or more PLMN types include at least one of a public PLMN type, a private PLMN type, and a public and private PLMN type.

9. A method of wireless communication, the method comprising:

reading system information of a plurality of cells on a first carrier frequency by User Equipment (UE) to obtain identification information of a plurality of Public Land Mobile Networks (PLMNs), wherein the first carrier frequency is an unlicensed carrier frequency;

reporting, by an Access Stratum (AS) entity of the UE, the identification information of the plurality of PLMNs to a non-access stratum (NAS) entity of the UE;

selecting, by the NAS entity of the UE, one of the plurality of PLMNs as the selected PLMN;

searching, by the UE, the plurality of cells on the first carrier frequency during a cell selection procedure;

selecting, by the UE, a suitable cell from the plurality of cells that belongs to the selected PLMN as a result of the cell selection procedure on the first carrier frequency; and

Performing, by the UE, a cell reselection procedure to select a new suitable cell, the cell reselection procedure comprising:

determining whether a highest ranked cell on the first carrier frequency belongs to one of the selected PLMN and a PLMN indicated as being equivalent to a registered PLMN of the UE;

selecting the highest ranked cell as the new suitable cell when the highest ranked cell belongs to one of the selected PLMN and the PLMN indicated as being equivalent to the registered PLMN of the UE; and

when the highest ranked cell on the first carrier frequency is not selected as the new suitable cell,

prohibiting the highest ranking cell from being selected as the new suitable cell for a first period of time; and

iteratively performing a process on the first carrier frequency until the new suitable cell is found on the first carrier frequency or a certain number of cells on the first carrier frequency are determined to be unsuitable cells, the process comprising:

determining whether a next highest ranking cell on the first carrier frequency belongs to one of the selected PLMN and the PLMN indicated as being equivalent to the registered PLMN of the UE;

Selecting the next highest ranked cell as the new suitable cell when the next highest ranked cell belongs to one of the selected PLMN and the PLMN indicated as being equivalent to the registered PLMN of the UE; and

and when the next highest ranking cell is not selected as the new suitable cell, determining that the next highest ranking cell is a non-suitable cell.

10. The method as recited in claim 9, further comprising:

when the total number of unsuitable cells on the first carrier frequency reaches the certain number, the new suitable cell is searched on a second carrier frequency by the UE.

11. The method as recited in claim 10, further comprising:

determining, by the UE, whether another highest ranking cell on the second carrier frequency belongs to one of the selected PLMN and the PLMN indicated as being equivalent to the registered PLMN of the UE;

selecting, by the UE, the other highest ranked cell as the new suitable cell when the other highest ranked cell belongs to one of the selected PLMN and the PLMN indicated to be equivalent to the registered PLMN of the UE;

When the other highest ranked cell on the second carrier frequency is not selected as the new suitable cell, prohibiting, by the UE, the other highest ranked cell from being selected as the new suitable cell for a second period of time;

wherein the length of the second time period is independent of the length of the first time period.

12. The method as recited in claim 9, further comprising:

when the total number of unsuitable cells on the first carrier frequency reaches the certain number, the first carrier frequency is de-prioritized by the UE in a set of carrier frequencies for a second period of time for the cell reselection procedure.

13. The method of claim 9, wherein the highest ranked cell and the next highest ranked cell on the first carrier frequency are ranked according to received radio signal quality, and the next highest ranked cell has a worse received radio signal quality than the highest ranked cell.

14. The method of claim 9, wherein the highest ranked cell and the next highest ranked cell belong to two different PLMNs of the plurality of PLMNs.

15. The method of claim 9, wherein the system information comprises PLMN type information indicating at least one PLMN type associated with the plurality of cells.

16. The method as recited in claim 9, further comprising:

providing, by the NAS entity of the UE, a message to the AS entity of the UE, the message indicating which of one or more PLMN types the UE supports;

wherein the one or more PLMN types include at least one of a public PLMN type, a private PLMN type, and a public and private PLMN type.